Redemption Demotion

Having a villain, especially a particularly threatening one, change sides is generally a good plot, and for three good reasons:
 * 1) It lets you introduce a "darker, edgier" hero.
 * 2) It reinforces our notion of the inherent goodness within people.
 * 3) It prevents the Worthy Opponent from falling victim to What a Senseless Waste of Human Life.

Unfortunately, a lot of the drama in such shows hinges on the odds being massively unequal: the bad guys always seem to have the heroes at a substantial disadvantage.

To set a villain apart from being an Ineffectual Sympathetic Villain or otherwise make them entertaining, he is usually built up as the equal or superior to all of the heroes, a serious threat to their team. Often, he's far and away the strongest of the Evil Minions our heroes have faced thus far.

And then he switches sides, and it all goes to hell. Suddenly, he's just one of the gang, not substantially stronger than the others. He's decidedly less powerful than the leader of the good guys. This phenomenon is related to Villain Decay.

Very common in RPGs, since the "playable" versions of the characters tend to have many fewer Hit Points, fewer and less impressive abilities, and generally worse stats than the "boss" versions. In older games, they even got physically smaller, since hero sprites were much smaller than enemy ones. Usually, this is a Gameplay and Story Segregation, since it wouldn't exactly be very fun to just pick "Mind Erasing Maimblaster" over and over again.

There are a number of possible, rational justifications for why a villain-turned-ally is suddenly weaker than before:
 * He loses access to the information network, resources, or manpower provided by his former side.
 * He isolates and confines his previous evil urges and habits into a Super Powered Evil Side that only occasionally rears its head.
 * If he was already relying on a Super Powered Evil Side, he resolves to never use it again (or at least reserve it for emergency use only).
 * If he was being driven insane by a source of power, curing him of the problem may render him sane enough to join The Hero, but will probably deprive him of that power too.
 * If he was using Black Magic or some other "inherently evil" power and has now decided to leave it behind, this also obviously deprives him of his former power. (Unless, of course, the situation crosses the Godzilla Threshold.)
 * Friction with new, untrusting allies as well as feelings of personal guilt and shame can leave The Hero's new buddy handicapped by insecurity.

However, sometimes no explanation is given at all. It could be worse though; if the Heel Face Turner is particularly unlucky, he'll just suffer Redemption Equals Death and that will be the end of it. From a story telling perspective, it's more dramatic to have the villains stronger than the heroes. But if the reformed villain remains more powerful than the hero, then the villain will outshine the hero and solve problems that the hero is supposed to solve. The depowering of the villain is a sort of Deus Exit Machina to force the hero to have a difficult struggle.

So remember, when you switch from bad to good, odds are good that your fighting will become bad.

If your character isn't exactly evil but a mere antagonist, they might fall victim to being Not So Above It All.

This trope can apply in reverse to characters traveling the other way, though, because Evil Is Cool. A character that does a Face Heel Turn will often find that they suddenly have ridiculous levels of power, enough to take down their entire former team single-handedly.

Sometimes, an enemy-turned-friend loses nothing of what made him a formidable opponent in the first place. This is usually because the character wasn't previously relying on any powers or methods that could be considered evil and thus which can continue to serve him as a hero.

Slightly rarer, a new ally goes through enough Character Development (or just Training From Hell) to acquire some new, heroic ability to replace his old ways, and can contribute to the cause from then on.

Compare Good Is Boring and Good Is Impotent. See also the Balance Between Good and Evil. Frequently accompanied by Badass Decay. Occasionally, a villain will get a Redemption Promotion instead.

Anime and Manga

 * Vegeta in Dragonball Z had destroyed dozens of planets, but when he turned good, he was left permanent second-banana to Goku. At one point, he willingly becomes a minion of the current Big Bad, pointing out that as a hero, he could only ever be second-rate, but he was a damned good villain.
 * That Vegeta is a better villain than hero is further highlighted by the fact that shortly after this he makes a second Heel Face Turn, in which he attempts to save the world via a Heroic Sacrifice. And fails.
 * To be fair, Vegeta doesn't drop hugely or suddenly in power, so it doesn't really fit this trope. Goku just kept getting stronger, faster.
 * Another example would be the debut of Yamcha in Dragonball. While initially posing a threat to Goku and then quickly turning good, Yamcha doesn't legitimately win an important non-filler battle in the next 400-something episodes, eventually rapidly fading from relevance.
 * To be fair, the main reason Yamcha nearly defeated Goku was because Goku was hungry.
 * Ditto Tenshinhan, who permanently crippled his first on-screen opponent, nearly did the same to Yamcha, and stood toe-to-toe with Goku in their first fight (and technically won), yet was quickly banished to Jobberdom. Only stayed in the big leagues due to his Kikouhou/Tri-Beam, which literally sapped the life from him. (And even then, later on, it was only good enough to sucker-punch Super Buu, who swiftly - and apparently permanently - returned the favor.)
 * Which is more than can be said for Chaozu, who didn't even win a single fight at all. That said, Tien, Yamcha and Chaozu do get a bit of redemption in a Filler episode where King Kai makes them go up against the Ginyu Force as a means of testing their training. And what's more, they win.
 * In fact, nearly all of Goku's allies were at least rivals to him, and frequently outright villains, when first introduced. And were credible threats to him. But after Defeat Means Friendship kicked in, they were quickly left in the dust by Goku.
 * Tokyo Mew Mew. Retasu. Just Retasu. Zakuro retained her ability to take out scores of Monsters of the Week at once, but did we ever see Mew Lettuce with the kind of power with which she just about killed Mew Ichigo and Mew Mint used against the bad guys?)
 * Yes, all except that aqua strike.
 * In Beyblade, just about anyone who fought the Bladebreakers and reformed. The most egregious examples in this editor's mind are the Saint Shields, who provided a legitimate challenge for our heroes when they fought them, but were thrown aside by the Big Bad, and Tala, who got demoted from Big Bad in the first season to Kai's second banana in the third. Then he got seriously wounded when fighting the good fight.
 * Played straight in Digimon Adventure 02, where the first Big Bad, who was in fact the Emperor of the Digital World, joins the team and is, for the most part, not able to defeat Digimon he would have earlier brainwashed easily. To be fair, part of turning good required giving up the massive brainwashed armies he would have used, as well as the Applied Phlebotinum he used to take control of them so easily.
 * It even turns out that Ken's genius and ability in sports was heavily (it's unclear how much precisely) augmented by his being infected with the Dark Spore. In the dub, Oikawa outright states that this is what made Ken a genius, so theoretically, with the spore dormant...
 * Also, in the original Digimon Adventure, Gatomon/Tailmon was capable of taking out the entire group of the Digidestined Champion-level Digimon, but when she joins the group, she has to Digivolve to Angewomon to take part in the battles. This is even worse in Digimon Adventure 02, where Gatomon loses her Tail Ring and is effectively reduced to the level of a Rookie for most of the series. She has to use a DigiEgg to have access to Champion-level power.
 * In Naruto there is a zig-zagged example Gaara. A psychopathic villain who would kill without a second thought, he severely injured one of the main characters, and it looked like he was about to kill Sasuke. After losing to Naruto, he becomes an ally, and loses the drive/ruthlessness/insanity that let him be so completely over the top in a quest to justify his existence with destruction. Even then he was doing better against Kimimaro than Naruto and Lee in Drunken Master mode - they could barely even hit him even when his curse mark wasn't active, and Gaara was mostly winning against him even when his curse mark reached Level 2. He lost to Deidara due to sacrificing offence in order to protect his city (leading to him ). He also became a Kage at age 15, beating Naruto to the punch, and when his rematch with started, he clearly had the upper hand due to . Ultimately,
 * Jun Manjoume begins Yu-Gi-Oh GX as a snobby but respected duelist in the Obelisk Blue dorms (the highest-ranked class) and a rival to Judai. As the series plays its course, Manjoume leaves the school, returns (but is forced into low-class Osiris Red), grudgingly becomes pals with the gang, and gains an obnoxious spirit partner in the form of Ojama Yellow. He also becomes something of a joke, especially when it comes to his crush on Asuka. At least Season 4 was about him regaining his old strength -- talk about coming full circle.
 * If you consider his track record while still in blue (two losses, the first at distinct advantage, and one near-loss) and compare it with his performance later on, it's more like Evil Is Dumb than anything else. Of course, Evil became smart when he temporarily joined the light cult.
 * Zelgadis from The Slayers, to a certain extent. While shown to have impressive powers while he still opposes the group and/or is in the plot's spotlight, once he joins the party he becomes close to useless combat-wise. Whenever he attacks, the attack usually accomplishes nothing, if only to show how powerful their adversary is. Also, his demonic ability to move faster than the eye can track seems to be largely forgotten, as it never allows him to dodge out of the way of incoming cannon blasts or spells while the rest of the party are unable to. The times when he does accomplish something in battle, it's usually something another character could've done just as well, be it shield or levitation. However, his decreasingly important role in battle is somewhat redeemed by the sheer variety of his skills, the hardiness of his stony skin (which enables him to take a cannonball to the head only to have it bounce off) and the fact that he's pretty much the only mature one in the group and often makes important discoveries and observations that the others had missed.
 * Avoided in Dragon Quest: Dai no Daibouken. When he leaves the dark side, Hyunckel loses some of his power; it's later explained to be a side-effect of losing the internal conflict that had driven him since childhood. When he finally finds a new reason to fight, he becomes more powerful than ever.
 * Freeze from Corrector Yui come from a ruthless, most dangerous and competent enemy among Grosser's henchmen into a bumbling chick who can't do anything right. Though to be fair, she's a program specifically designed to be bad, so when she starts something good...
 * Usually played so straight it hurts in Kinnikuman, whereby a character trumped up to be an analytical genius killing machine cyborg proceeds to lose every damn fight after his Heel Face Turn except for one. The reason for that was losing his memory and snapping back to his original brutal nature for part of the fight, thereby showing no restraint in mauling the opponent severely.
 * A notable exception is found in the early enemy wrestler Ramenman, however. The authors were originally going to use him only for the first Tournament Arc, but proved so popular they brought him back as a hero, at which point he usually kicked someone's ass left and right without breaking a sweat once per arc.
 * Renji from Bleach is an example of this trope, albeit a justified one. By the time he comes around to the good guys side, the only baddies left to fight are the ones that would have kicked his ass even when he was on their side.
 * Renji is an interesting case when you consider that before his full Heel Face Turn, he doesn't win a single fight on screen. His only victory was an off screen fight against Ishida in the first arc. Also worth noting is the fact that, yes, the first two fights he engages in after his face turn were against captains. He also ended up fighting two Espada, one of which was technically the top ranked and the other wouldn't engage him at all unless he knew going in that he would have an unbreakable advantage.
 * In One Piece, Nico Robin won almost all of her fights easily, had one of the highest bounties in the series, and was the second highest ranking member of Baroque Works before joining the Straw Hat Pirates. Afterwards, she can't keep up with the stronger characters anymore.
 * This is partly the result of her joining relatively late, when the series is seemingly moving away from one-on-one battles and having more opponents that none of the Straw Hats except (and sometimes even including) Luffy can defeat. She's still roughly in the middle of the crew in terms of strength, but there are fewer enemies she can hope to take on by herself.
 * Despite being able to present a threat to the heroes when they fought against them, Buggy, Mr. 3 and Mr. 2 are barely able to take on the Mooks of Impel Down, whom Luffy is able to defeat almost effortlessly.
 * Kind of averted and justified with Buggy and Mr. 3 since they are cowards who fight strategically. Mr. 2 helped fight wolves who were attacking Luffy in level 5, using his powers to slip past the guards, and helped Luffy during his hormone healing. Mr.3 powers proved useful in the battle against the Warden and Buggy helped transport Luffy in the first floor liberated, and inspired other prisoners to rebel. So while they didn't have the brute strength of Luffy the 3 helped in other aspects during the arc.
 * Magical Girl Lyrical Nanoha is generally good at averting this, with Fate, Arf, the Wolkenritter and Nove not seeming to become any less effective after their Heel Face Turn. Played straight however with . When she's on the evil side she had Nigh Invulnerability and a city-sized Starlight Breaker. As a playable character on the good side in The Battle of Aces... not so much.
 * It took some time but it got finally played straight with the Wolkenritter. In Striker S it was stated they've started to lose some of their healing factor and is implied their other powers will also start to weaken from that point onwards. They still managed to remain among the strongest characters during that season with impressive feats of damage endurance. Then came FORCE and the bad omen finally started to become true with them being showed to be significantly less powerfull and resillent to damage than before (formerly able to take killing blows like nothing, both Vita and Signum got easily downed after a mere couple of slices).
 * Inverted by Viral in Tengen Toppa Gurren Lagann. After he joins Team Dai-Gurren, he actually turns this into a Redemption Promotion.
 * Lordgenome does it too, as he becomes even more badass after the time-skip. The fact that he's a head in a jar only makes it even more impressive when he later sacrifices himself to turn a Big Bang into a huge power-boost.
 * in To Aru Majutsu no Index. Five minutes after deciding to stop being a jerk BAM! Brain damage. H
 * While Jelly Jiggler from Bobobo Bobobobo was always pretty silly, he at least had some chops when he was a villain. After he turns good, though, he becomes the biggest Butt Monkey in the series.
 * For the sadly brief period they were on the good guys' side, Crona had his/her strength decreased and stood up to Giriko marginally longer than Maka. An indication of how strong Giriko was being that he managed to cut Crona. The black blood had previously been damaged only by Maka's super-powered evil side and Death Scythe. The demotion was explained in the anime by Maka's special soul wavelength, and in the manga by Shinigami taking the souls Ragnarok had consumed. Crona's state following their Face Heel Turn would suggest they've 'improved' dramatically, Black Star's approach notwithstanding ('stronger than', apparently, 'reasoned with', hell no).
 * Rurouni Kenshin: Partially averted with Saitou (since he wasn't really a villain). After allying with Kenshin, he's still one of the most effective fighters, finishing off Usui in one of the shortest battles in the series.
 * Double subverted in Suite Precure. When Siren changes sides and becomes Cure Beat, she's quite Badass and crushes the Monster of the Week easily two or three times, even finishing them off herself! After a dozen or so episodes later, she's the one getting defeated by a single Monster of the Week and Cure Rhythm and Melody have to bail her out.
 * Cure Muse is a neutral-to-good example, but otherwise she plays it awfully straight. Se spends half the series being a Mysterious Protector and a Badass, but the very first battle she's in after joining the main girls, it begins with her getting punched off by the Monster of the Week. Then her Special Move is ineffective and is told she has to rely in others. She eventually kills the Monster of the Week on her second try, but not before making it clear this trope is in effect. At least Ellen was awesome for a while!
 * While we're on the subject of Pretty Cures, poor Kaoru and Michiru of Futari wa Pretty Cure Splash Star. They get their Heel Face Turns, save the day with Saki and Mai... then get Demoted to Extra come the Pretty Cure All Stars movies.

Comic Books

 * Juggernaut, in the X-Men comics, was a literally unstoppable force. Basically the only way to defeat him was to trick him into going away (or, to be fair, to remove his telepath-blocking helmet, but getting the thing off generally necessitated a battle royale). After going through a Wonderful Life montage, he repented his evil ways and joined the good guys' side. Despite formerly being able to take out entire teams of superheroes by himself, he was now having trouble taking on solo villains as 'part' of a team. Justified in that the evil god who gave Juggernaut his powers was displeased by his servant's kinder, gentler personality and was slowly removing his powers. He's since made a Face Heel Turn and is now scaled back up to his full power.
 * When Juggernaut was at his most evil he could go toe-to-toe with Hulk or Thor, when he was at his most good with New Excalibur he got his ass handed to him by the Wrecking Crew, a C-list group of super thugs
 * Similarly, long-time X-Men adversary Magneto is one of the most powerful mutants in the Marvel Universe...except when he switches sides.
 * Justified, up to a point, by the fact that using his powers at high levels messes with Magneto's brain chemistry and makes him act crazy. In other words, the more stable his personality, the less powerful he is.
 * The few times that Magneto's daughter, the Scarlet Witch, has gone insane and became evil, she turned into a force of nature. When she's a hero, her abilities wax and wane Depending On the Writer.
 * It must be a genetic thing. When Magneto's other daughter, Polaris, first showed up as a Brainwashed and Crazy villain, she was as powerful as Magneto himself. After she snapped out of it and joined the X-Men - not so much.
 * In her first appearance, a villainous Rogue took on the entire Avengers by herself and was a major force in her early encounters with the X-men. Then she joins the X-Men and is thereafter beaten up by all subsequent villains to show how tough they are (okay, slight exaggeration). Justified (a bit) by her being less willing to use her increasingly problematic absorption powers.
 * Averted or inverted in the case of the various members of Thunderbolts. Most of the members have been b-grade villains. Once they became heroes (or were forced to join the team), they became much more competent or at least remained as powerful as they were before.
 * The Spider Man villain Sandman is an aversion. There was a long time in which he was a hero and even a reserve member of the Avengers, . During this time, he was just as powerful as he was while a villain. He was the powerhouse in Silver Sable's Wildpack and was shown to be the only member who could hang with Venom in a fight. He was also the only person to defeat a version of Doctor Octopus who had become extremely powerful and had defeated several other heroes.
 * The USAgent first showed up in Captain America and while he was not a full fledged Big Bad, he was still an Anti Hero with shades of Sociopathic Hero due to mental tampering. In this state, he was a stronger and more evil version of Captain America who had a great deal of trouble bringing him down. Once USAgent calmed down a little, joined the Avengers, and became more of a standard hero, he was quickly turned into Captain America-lite. In one recent issue, Captain America was implied to be stronger despite USAgent having superhuman strength as opposed to Cap.
 * Namor was technically an Anti Hero at first but once he was brought into the Silver Age of comics, he was a villain for a few years. As a villain, he could single-handidly defeat the Fantastic Four and was dangerous enough that the the Avengers would go out on patrols looking for him. As a hero, he often ends up in Worf Effect situations and is usually not as powerful.

Film

 * One of the worst examples of this is in the James Bond film Diamonds Are Forever. The main Bond girl is Tiffany Case, a professional diamond smuggler. In the first half of the film, she's shown to be a seasoned pro, good at her criminal work, with enough authority to even have her own henchmen. Late in the film, she successfully (and cleverly) eludes a crowded auditorium loaded with CIA agents ready to arrest her. After she turns good, her brains go south, particularly over a mix-up with cassette tapes. This prompts both Bond and Blofeld to make snide remarks about what an "idiot" she is.
 * Averted by Godzilla, who's generally one of, if not the most powerfu Kaiju when he appears, no matter whether he's good or evil. In full force with King Ghidorah, however. Despite significant Villain Decay over the years (it used to take 2-3 monsters just to stand a chance against him), he still generally managed to put up a good fight against Godzilla (even in the Hesei film, he managed to strangle Godzilla until soap suds came out). But in Godzilla-Mothra-King Ghidorah, he was one of the good monsters; and got profoundly curbstomped. Then he came back from the dead stronger, and got curbstomped, AGAIN. Then he came back, even stronger, and he got curbstomped a third time. Justified in that originally, lower-tier monsters were supposed to be used in place of Ghidora and Mothra, but Toho execs wanted to use their most popular monsters.
 * Hellbound Hellraiser II presents an extremely glaring example. Near the climax, the heroine talks the four main Cenobites of the previous film- including Pinhead, the series' most popular villain- into a Heel Face Turn by reminding them they were once human. Minutes later, they are unceremoniously Curb Stomped by a newly-converted and thoroughly evil Cenobite. The screenwriter received so much hate mail over this, he wound up invoking Worf Had the Flu.

Literature

 * Averted in later Artemis Fowl books, when Arty is just as competent despite now being a full time hero.
 * But disturbingly mushy.
 * In Xanth, the Dastard is one of the smartest and most powerful villains in the books. Then he gets his soul back, turns good and gets his original talent of having bad ideas back.

Live Action TV

 * Power Rangers, every single time they did the "evil ranger" plot. The original Green Ranger nearly killed the heroes in five-against-one fights, but the second he switched sides, he was weakened immensely. Ditto the Titanium Ranger, the Wild Force Wolf Ranger, the Thunder Rangers, and Dino Thunder's White Ranger.
 * The Green Ranger actually got handled pretty well, mainly because he was basically only called when the going got tough (read: damn near every battle). The only real thing he lost was the power of darkness, and the reason for that is obvious. When he became the White Ranger though...
 * Dino Thunder is an odd duck, since in the source material, the White Ranger (Abarekiller) technically never joined the heroes (and thus remained strong enough to fall victim to Marty Stu accusations). Thus, Dino Thunder had to resort to the plot of an Evil Twin to justify all the footage where he fought the Rangers despite their version being forced to join the good guys earlier via Executive Meddling.
 * He's a rare case with a justification. His super-powerful Dino Gem was driving him evil, but when he was punished by the Big Bad via an energy draining device, weakening the gem led to him returning to normal... with powers reduced to standard Ranger level.
 * It should be noted that when the Sixth Ranger is good upon introduction, it's no different. He schools whatever enemy the starting five Rangers couldn't beat, looks awesome doing it, and it will continue in the next episode as we are getting properly introduced to the character. Immediately after that, he's no stronger than any of the main five, and is often even subjected to The Worf Effect.
 * Happens in record time in Kamen Rider Decade. Yuusuke is Brainwashed and Crazy and upgraded to Rising Ultimate Kuuga. He floors several Riders just by gesturing in their general direction. When he's restored to normal, Shadow Moon soon attacks and schools him and Decade easily.
 * In an episode of Angel, Wolfram & Hart create a diversion to distract Angel while they extract vital information from Lorne's mind. Angel completely falls for this ruse despite its similarity to one that Angelus used on Buffy in "Becoming". Indeed, Angelus often seems a bit more clever than Angel, perhaps because Angelus is not burdened by any loyalties to his friends. A lampshade was hung on this in Season 4, with Cordelia observing that Angelus is "smart" and Angel taking umbrage.
 * Angel's often portrayed as not too bright though and Wesley (the guy employed to be smart) outright states that Angelus is smarter than him. Most likely explanation is that Angelus is extremely bright but often tripped up by being Ax Crazy.
 * Another possible reason is that Angel is burdened constantly with guilt over everything he did as Angelus. The constant feeling of guilt and thinking about all the sins he committed would likely overwhelm him and cause him to perform at a lower level.
 * Presumably the demon that possesses Angel is the smart one? As shown in several flashbacks, Angel wasn't a particularly bright (or charming) man before he became a vampire. And it isn't just smarts; Angelus seems to be a better fighter too.
 * If Pylea is any indication, the demon within Angel only has beast-like intelligence, much like a rampaging werewolf.
 * Angelus is smart at being evil. Angel is Angelus with a soul leashing him. He has all the same demonic urges, but spends his time not acting on them. It's like an addict spending a lot of energy doing what a non-addict considers easy; not succumbing to addiction. Angelus is an artist, the mindfuck his medium, murder his paintbrush. Angel is, too, but that's not going to help the good guys, now is it?
 * Connor, also from Angel, personified Redemption Demotion. As a conflicted character, he was constantly switching sides; when fighting at his father's side he was a bit slower than Angel and not as agile, but when he fought against the good guys he was like Spider-Man with a cause, decking multiple foes with each blow and always one step ahead.
 * Illyria in Angel too. When she was first introduced, and seemed as if she'd be the Big Bad of the 5th season, she was downright godlike in her invincibility. Wolfram and Hart, the main villains of the entire series, were collectively so weak in comparison as to be like insects to her. There were other characters in Buffy the Vampire Slayer and Angel who were actual gods, and Illyria could've overpowered any of them. Basically, she was Cthulhu in a cute human girl's body. But when she ended up more or less on the heroes' side, it's quickly revealed that her new, human body can't handle that level of power, and she gets powered down to the point that a minion of Wolfram and Hart is able to beat her into the ground. Justified because she was zapped with a power draining cannon.
 * Spike's fall was so severe this wiki named a trope after it. Eventually Buffy tells him "I want the Spike who's dangerous, the Spike who tried to kill me when we first met." She more-or-less gets him for the remainder of the series, as by then the Sorting Algorithm of Evil has rendered him no-longer overpowered.
 * A particularly weird example occurs in Heroes. Peter and Sylar are both immensely powerful, but it's dealt with by keeping Sylar as a villain and handing Peter the Idiot Ball. When Sylar was given a Heel Face Turn, the writers suddenly noticed the trope and turned him back in order to hijack the plot.
 * As of the season 4 finale, they've tried to redeem Sylar again. He's been angsting about getting rid of his powers though, so presumably the trope will come into play.
 * Subverted in Star Trek Deep Space Nine - Damar is initially nothing more than Dukat's boorish second-banana, then a puppet ruler chafing under the oversight of his Dominion "allies", turned to drink just to get through the day. Once he betrays the Dominion and founds the Cardassian La Résistance, he gradually overcomes these flaws and becomes a genuinely inspiring, patriotic hero who galvanizes the entire Cardassian race into a last-second Heel Face Turn, just before his Heroic Sacrifice.
 * Castiel suffered this in Supernatural's fifth season. The show justified it by claiming that his powers were diminishing due to being cut off from Heaven.
 * Allan-a-Dale from Robin Hood became a lot less smart once he joined Guy of Gisborne and the Sheriff. The outlaws still managed to run rings around them, even though they were still using the techniques that Allan was familiar with. Of course, you could argue that Allan was deliberately sabotaging himself for the sake of his former friends...

Professional Wrestling

 * This happens a lot in Professional Wrestling too; after a Heel Face Turn, the new face proceeds to fall for all of the tricks that he perpetrated as a bad guy. See Chris Jericho.
 * Subverted by Batista, who turns face and, thanks to being Genre Savvy, anticipates and counters the heels' tricks.
 * Also subverted by Eddie Guerrero's final face turn, as he continued to use all the dirty tricks he used to... except that now the fans were cheering him for it.
 * Of course, the flipside of this is that a wrestler who was able to get clean wins as a face will only be able to win by cheating after a Face Heel Turn.
 * Reputedly Lampshaded by Ric Flair, who said he didn't cheat because he needed to, but because he could.
 * Lampshaded by Diesel after he got beat by Bret Hart for the World Title. Diesel claimed that he lost his edge while trying to be Vince McMahon's latest reimagining of Hulk Hogan, and that he was going back to being the Badass that effortlessly cleared rings during battle royals. He has since then became a Tweener that gradually transitioned into a full-blown Heel.
 * Also Lampshaded by Sting in the dying days of WCW who, after years of everyone in his life turning on him, finally got ahead of the game by seeing Elizabeth's Face Heel Turn on him from the same million miles away that the audience did.
 * Subverted and played straight at the same time when Sting was exiled from the Main Event Mafia in TNA. He offered MEM member Kevin Nash a ball bat and turned his back, testing whether or not Nash would have the courage or lack thereof to hit him from behind. Sting had a second ball bat concealed in his trench coat which he used on the Mafia when Nash was about to swing. Trope is still played straight in the fact that Sting was still in a six-on-one situation and when the Mafia got the advantage, they had TWO baseball bats to use on Sting.
 * Subverted by The Undertaker, as regardless of his status, he's the most powerful wrestler on the card.
 * When a monster heel is brought into the company, he wins nearly every match, with many of them being squash matches. After his face turn, he will become easier to beat and his win/loss record will show that (e.g. Yokozuna, Vader, Great Khali, Mark Henry, Vladmir Kozlov).

Tabletop Games

 * Magic the Gathering: Rhys the Exiled is a powerful elf from Lorwyn. Following the Aurora, which converts Lorwyn into the bleak Shadowmoor, he becomes Rhys the Redeemed, with significantly reduced strength and durability. (Although it has to be admitted he does have some interesting, potentially very powerful abilities.)
 * Dungeons and Dragons 3rd Edition: Normally, monstrous creatures (or just atypically powerful races) suited for use as player characters have "Level Adjustment", a number of "virtual" levels to count them as already having (added on to their racial hit dice) before adding class levels, to balance their innate prowess. In many cases, however, monsters' LA is badly overestimated. They often would have gained much more by an equivalent number of levels in an actual character class, meaning that when controlled by players, they often are very weak for the party's level. This problem can be exacerbated by racial hit dice, which provide the monster's core abilities (hit points, attack bonus, etc.) and count as effective levels, since they provide no other direct benefits and some racial HD types are vastly superior to others. Under-estimated LA, and/or very powerful HD types (dragons, outsiders, and magical beasts being strong contenders), and/or good synergy with class features can cause this to be inverted.
 * More directly exemplified in the "Savage Species" supplement, which introduced an alternative to make monsters playable at low levels, by allowing you to gradually earn the abilities represented by a monster's level adjustment by gaining levels as a monster instead of in a character class. In short, the creature is intentionally demoted to bring them theoretically on par with normal characters, gaining portions of their full innate power instead of class levels. The aforementioned level adjustment just causes the monster to gain less than a conventional character might have, rather than actually demoting it.

Video Games
"Agrael: How sad it is that I, the ultimate servant of evil and commander of the demon invasion, is reduced to weak buffoonery as soon as control is given to the player."
 * In Heroes of Might and Magic V an infernal general Agrael in the end of his campaign decides that he had enough of his demonic masters, bails and switches to being a Warlock (well, the best he could get in his condition and he turns out quite a nice guy for a Dark Elf). Naturally, he loses all his abilities, even not demon-related, and levels of experience in the process and has to start evolving from scratch. Explained in-story as the effect of the ritual that purified him of demon taint.
 * The same happens earlier, at the start of his own campaign: formerly a formidable hero in Isabel's campaign, he is suddenly brought down to level 1. There is no story justification here.


 * Particularly egregious example: Magus in Chrono Trigger was an incredibly badass boss, but when he joins you, he has significantly less HP (going from 6666 to at most 999), and he has to relearn all but three of his spells. This is explained by having his powers weakened by a Masamune beating and drained by Lavos, while the discrepancy in the stats are explained by simple game mechanics and ratios: enemies and bosses have more HP, but the main characters do more damage.
 * Exception: The Super Robot Wars games occasionally reward the player for superior performance (or just satisfying extremely obscure requirements) with a playable boss character who retains his or her boss abilities and stats. Notable examples are Neo Granzon in Super Robot Wars Gaiden, the Astranagant in Super Robot Wars Alpha and Nashim Gun-Eden in Alpha 3, all of which are at least an order of magnitude harder to kill than any other unit in the player's army.
 * The same series also plays it straight with non-bonus characters; one of the more extreme examples is in Original Generation 2, where a boss character who pulls a Heel Face Turn goes from having 100,000 HP to 5,500 - in the middle of a battle.
 * An exception also comes up in Super Robot Wars Reversal (SRWR). After fighting the rival robot of Gear Fighter Dendou, Gear Fighter Ogre, you can get it and it's stats will go down but if during a route split you choose to fight the possessed Subaru who is using Ogre after the battle you get him back and find out that the bad guys put Ogre back to the stats it had before and you get to keep them this time.
 * Reversal also hangs a lampshade over this trope: if you're able to rescue Master Aisa and revive him with Jin Getter Robo, they rebuild Master Gundam for him to use, though Rain points out that it isn't as strong as his original Master Gundam (which was not only DG Cell-powered, but also a boss unit in other games.)
 * Utterly averted in Super Robot Wars J, where the big bad's Dragon undergoes a Heel Face Turn in the final battle and fights on your side; His machine still has the same 50,000 HP it had when you fought him, and he deploys with full Morale, allowing him to use the same devastating moves he used on you. Further, Gale and Julia of SPT Layzner have the same stats they had as bosses when they join you.
 * Played straight in the same game with Johnny and Yuu's sister from Brainpowerd, who's Barons are more powerful than all but Nelly Brain, but are nowhere near the 60k they exhibited as bosses.
 * Played straight in the inverse in Super Robot Wars Original Generation when pulls his Face Heel Turn and steals the R-Gun to boot. The machine's stats are * way* higher than they were five seconds ago when you were using it.
 * Played depressingly straight in the true final stage Super Robot Wars W. After Critic deposes Inference and takes control of the Sapientia, Applicant shows up in the Val Arm to give you a hand. Naturally, the machine is many times worse in every respect than it was as the final boss of the previous stage, and Applicant himself is demoted as well, with lowered stats, fewer abilities, and missing his Double Move skill as well as his face cut-in. Also, he gains Main Character status and is not allowed to die. Oi.
 * Folka in OG Gaiden plays around with this. As a boss he has well over 100,000 HP taking very long to kill but only has two relatively weak basic attacks so he's no real threat to your guys. Upon joining you his HP drops to the PC average of 6,000 but he also unlocks his incredibly powerful Fist of the North star type attacks (which he seemingly could always use but just didn't feel like it as a bad guy) causing him to do insane amounts of damage.
 * Kurtis in Disgaea is a ruthless boss (with a matching level), but when he eventually joins your team, he becomes much less effective. Probably because
 * Maderas and Hoggmeiser have considerably more HP as bosses.
 * Justified in Disgaea 2, where such a Heel Face Turn was the result of a loss in power by pseudo-antagonist Etna. Even then, she only hangs around the protagonist and his entourage until she regains her former power (descriptions of which are rife with fourth-wall breakage).
 * Present in Disgaea 3 DLC characters. You're prompted to fight them before they actually become playable, and while facing them as enemies, they sport very strong and rare weaponry, have the strongest weapon skills at their hand and have between 10.000 to 25.000 HP to boot. Once they become playable, they lose all their equipment, lose all of their weapon skills and their HP is cut down to an average of 3.000.
 * Do note though, as in the prior two games, once the character in question is yours, you can train the character back up and give them equipment that far outranks whatever they had as a boss. And when you eventually cycle back through the game and acquire them again, they'll be at the same level with all their gear.
 * As with the Disgaea examples, every secret character you can get are high or very high level (with the exception of Asagi, who is only level 50) when you have to fight them, but drop to level 1 and lose their stuff when they join you. Makes sense for several of the Overlords (as you're actually gaining a "phantom copy" of them), but not for Laharl and company, who join as themselves. Even the Robosuit reverts to level 1 after you claim it.
 * Hot Blooded Matsu from .hack GU is an Adept Rogue, with the ability to use Broadswords and Steam Guns, the former being his preferred weapon from his Player killing days. However, when he joins Moon Tree, he becomes a pacifist and stops using it. When you get his member address to call him into your party, he can still only equip Steam Guns. The problem here is that Adept Rogues learn moves for their chosen weapon classes at a slower rate because their actual strength is their ability to use multiple weapons, so Matsu is essentially an extremely weak Steam Gunner in comparison to your other, actual Steam Gunner.
 * He'd also become your only Edge Punisher if he could use Broadswords.
 * Though he has the ability to equip heavy armor, something steam gunners can't do.
 * Tales of Symphonia has a few rather blatant examples of this with . What makes it strange is that is fought both in a normal and solo fight, and when fought solo, Lloyd tells him not to hold anything back, but he not only has only 1/4 the HP he has in the normal boss fights, but appears to have taken considerably more damage when the fight is over.
 * Potentially even worse than the above is . Despite the fact that he was in your party two minutes ago, he's suddenly got five-digit HP and tons of kickass moves. A Hand Wave is attempted by the fact that he's now using angel powers, which he doesn't do with the party, but it's still jarring.
 * Tales of Destiny pits you against Leon Magnus, a genius swordsman who is tasked with kicking the snot out of the hero and his party. Given that this happens within the first few hours of the game, the party isn't even near the level needed to wear down his 9999 health points and survive his attacks. However, once he joins you, his level and stats are barely any higher than those of your other characters.
 * The Remake gives this more of a realism by reducing the boss version's HP and statistics to around what they should be when he joins the party, and instead just made him literally unbeatable.
 * of Tales of Vesperia is an odd example -- although he's not evil in the slightest. In the one instance when he joins you in combat, he has somewhere around 5000 HP and a paltry amount of Artes. Approximately one day later in the game's timeline, he and Yuri duke it out -- and he's suddenly gained six-digit HP and a repertoire of deadly Artes, including Holy Lance and a Mystic Arte, Radiant Dragon Fang. He must've done a buttload of Level Grinding in that one day.
 * Captain Schwann exemplifies both this trope and Evil Is Cool. As a boss, he's incredibly difficult (although most of the difficulty comes from the fact that both your healers are absent from the party), has six-digit health, and extremely powerful techniques. He's missing most of those techniques and is back down to four-digit health when . Justified in that he's using his Dangerous Forbidden Technique during the battle, and wielding his sword in the other hand.
 * In the PS 3 remake the final team arena battle pits you against the party members you don't currently have with you. Not only do they have boss class hp and stats now, but they break the party size limit to attack you with ALL unused members making the match 4 against 5. The party seemingly puts more effort in friendly arena match than against the guys that want to destroy the world.
 * Lunar: Eternal Blue has this with Leo... but in fact averts it in that Leo appears to be Level Grinding at the same rate as the protagonist, and when they duel one on one, Leo only has about 288 HP... around the same as he did when they teamed up. But the Playstation version undoes this by giving Leo about 750 HP for the duel... of course it was anticlimactic as one can use a technique and oneshot Leo.
 * Zero from the Mega Man X games is at his most powerful when he's fighting against the player: he even has access to moves that the playable Zero is never able to use. In X5,
 * Potentially justified, depending on how you view it. X and Zero are both well-aware of each other's capabilities, which means that they are forced to go all out against each other, using techniques they would not use otherwise. Of course, the real reason is that the player needs to be challenged, but, well, it's potentially justifiable...
 * If that's why, they got themselves killed in same game by not taking Sigma seriously enough to use said tricks. Good is REALLY dumb!
 * The playable character finally gets to use Zero's boss moves after defeating Bonus Boss Omega (oh, and clearing the game) in Mega Man ZX. It is GLORIOUS.
 * Zero is justified in both situations. In X2,
 * Seen also in Mega Man Powered Up, if playing as one of the other robots. In the place of The robot master you're playing as, you'll fight against an evil Mega Man wearing a purple scarf. He can charge his buster, Slide, and is quite the pain in the ass.
 * Similarly, in fellow Capcom game Devil May Cry 3, the playable version of Vergil (accessible in the Special Edition) lacks moves that the boss version can do. However, playable Vergil does get some moves his boss incarnations don't, and the series also tends to make Dante, the hero, far more Badass than any evil counterpart.
 * Variation: One of the drama CDs of Guilty Gear depicts an Alternate Universe in which the character Dizzy -- a sweet, innocent Friend to All Living Things in the games -- inherits the title of Big Bad from her mother. In the games, she's more or less toe-to-toe with the rest of the characters (sort of), partly because she's trying to suppress her powers so she doesn't hurt anyone -- although this doesn't seem to change drastically when she goes berserk in the third game. In the Alternate Universe, she singlehandedly destroys a fleet of airships using one move.
 * Nitros, from the game Bomberman Hero. During the game, he's quite a hard guy to defeat, using all kinds of weird powers. But at one point, after you defeat him, he realizes he's been brainwashed and adds his power to yours. But do you get any special board-game based attacks? Nope, you get to lay more bombs. The funny thing here is that you'd have to be more powerful than him to defeat him in the first place. Also, as soon as you next die or turn off the game, you lose all that power. And you don't get any power from beating him another time replaying the level - it only happens when you first trigger the cutscene.
 * In Ultima VII Part II, Selina the sorceress briefly joins with you early in the quest, is absolutely worthless at doing anything, and teleports out when the going gets tough. Later on, she turns up as an antagonist, and is surprisingly effective at that.
 * Very easily justified by the fact that she is an antagonist from the very start (she is leading you into an ambush, after all) and has no reason to help you with anything other than to get you to the ambush point. In other words, she is holding herself back.
 * In Arc the Lad: Twilight of the Spirits, Tatjana as well as many of Darc's allies have this to some extent, but many of them have just had no real affiliation with the villains before meeting Darc, and Tatjana had merely been betrayed as a wake-up call. Tatjana is seen as one of Dilzweld's commanders and is capable of mutating a deimos into a state where it is completely unrecognizable. She is also fought as an enemy on Darc's side, but in fact it is revealed that a lot of her power comes from having her advanced science (that is not portable) and from being able to command soldiers, since when she is a guest-party member in Kharg's group at first she is easily picked off by the boss monsters unless saved.
 * There is also another part in which you have to fight the opposing party. Of course they are about as strong as they were when you left them off.
 * Subverted in Zone of the Enders Fist Of Mars: It's possible for the villain's cohort to Heel Face Turn, and although she loses her powerful boss mech, she still maintains her well-above-par stats. On the good path, you can recruit someone in a boss mech with an absurd amount of hp (20000, when the others have like 5000) and strong attacks, and in the next fight she will be at full strength. Although she'll have trouble hitting the fast final boss, she will take a ridiculous amount of attacks and OHKO the minions. Also, this game subverts Evil Is Cool.
 * Averted in the 10th Fire Emblem. The Black Knight (a boss from the 9th game that is arguably harder than the final one but is somewhat optional) briefly joins the party to protect Micaiah. The only thing that stops him from being a Game Breaker is that he's a classic Crutch Character: he takes away experience points (in a game where they are limited) from horribly under leveled units that desperately need it.
 * In Fire Emblem 7, Vaida is an enemy with greatly increased stats, the boss of a "survive" mission (i.e., you don't have to kill her to win, so don't even try because she has at least + 5 to every stat). When she joins a mission later, she is thoroughly mediocre. Justified in that she was powered up by the Big Bad's magic.
 * In an unintentional subversion, the player can use a glitch to steal Vaida's Spear, the item that was coded to increase all of her stats (dubbed the "uber spear" by fangroups), and give it back to her in the next mission, allowing her to retain her beastly stats even while Good.
 * Typically always averted in the games. None of the units that you can recruit from the enemies will ever get degraded stats from what they had. In fact, on harder difficulties, enemies have higher stats... including the ones willing to join you.
 * Similar: In Puzzle Quest: Challenge Of The Warlords, you'll often find that after capturing an opponent, the uber-spell you were hoping to learn from it isn't available. (for instance, you can't learn Deathsting from the Giant Wasp or Breathe Ice from the Frost Dragon). Also, since the mana costs of learned spells are 50% higher than from "natural" use, often you won't have enough of a certain level to use it, even with full mana levels (Ex: You need 30 Blue Mana to use the Call The Horde spell, but Orc Lords only need 20) or the cost per attack isn't worth it (Rend is deadly in the hands of a Wyvern, not so much in yours).
 * Justified in Legend of Spyro: A New Beginning. The villain for almost the entire game, Cynder, is actually a baby dragon, mutated into a powerful adult-like form by the powers of the actual main villain. Once she is defeated, she is cut off from these powers and reverts to her natural younger-looking, weaker, and much less badass form. She remains in this form throughout the ending and subsequent Spyro games, where she is a protagonist.
 * Averted in Final Fantasy IX with Worthy Opponent Beatrix, who proves to be more than a match for your party as you battle her time and time again. However, when she realizes the ruler she has sworn fealty to has gone mad, she joins your party, and proves to be every bit as powerful as she was when you fought her. Sadly, she doesn't stay long.
 * Of course, her MP seems to take a nosedive upon joining you, meaning that she can't use her frighteningly powerful sword skills as often as she could when she was against you...
 * At least you can swipe her goods from her before she leaves for good. However, her kickass sword can't be removed, and the rest of her equipment is fairly sub-par if you managed to get all the best items to date by the time you get to move her stuff.
 * Certainly not averted in Final Fantasy VIII -- Edea the Evil Uber-Hot Gothy Witch Queen Fetish Fuel chick is the Big Bad of the first act -- and turns into a rather weak playable character thereafter (additionally no longer ruling the world). It's rather a disappointment when you unlock her and think "Oooh, yay!" and then end up with a somewhat wussy sorceress.
 * If it's not averted, it's justified, at least. The reason she becomes good in the first place is that she loses all her sorceress powers which made her powerful (and brainwashed) to Rinoa, thus making her a normal human being. When Squall tries to physically stop the brainwashed Rinoa from leaving the lunar base, he gets launched into the nearest wall. However, when you get Rinoa back, she isn't one bit more powerful than before (except for having a new Limit Break).
 * In her limit break, however, has five times her magic stat (beyond the normal cap of 255), and slightly enhanced speed. Unfortunately, for most people, this limit break will be useless, because she casts spells semi-randomly. 9/10 she'll cast scan, over and over, as opposed to spells that actually hurt enemies. Due to the Cap on damage, even if you remove all the useless spells, and fill her up with ultima or firaga or tornado, it's Awesome but Impractical, as you'll do 9999 damage instead of 8000 in a game where 100000 is a decent amount of boss health. The Health Damage Asymmetry hurts you a lot. If, however, you use meltdown, a spell that weakens enemies, and meteor, a spell that does 10 weak hits, and boost her speed up with haste and speed junctions, she can do 99990 damage per round, and that several times a second. You can then defeat the ultimate sorceress' 1st form in 1/3 of a second, second form in 2/3s of a second, and third in one second.
 * In Kingdom Hearts Chain of Memories and Kingdom Hearts II, Riku loses most of the independence and ambition that he had when he was on the Dark Side, and leaves all the hero work to Sora (though he does regain his cool at the very end of Kingdom Hearts II, but still...)
 * The same can be said about Roxas, as when he is fought as an enemy in the No Export for You version, he's far more powerful than when you played as him.
 * Also
 * Lu Bu in Dynasty Warriors 2-6 -- In one map he's a virtually unkillable super-armoured warrior in constant Musou Rage who can kill you in one or two hits. Then you unlock him and get the version balanced like everyone else (however, since he's so cool as the NPC version, most people will mac him out ASAP anyway -- but he's STILL not as tough as the NPC version (though if played well with pre-considered access to Musou Rages and the right balance of magic stuff, he can sometimes kill his other self--just barely))
 * This is the case with more than just him though. Good luck getting Guan Yu to be as good as his Fan Castle iteration or Zhang Liao and Gan Ning to do the same for their He Fei forms. Generally if a general was famous for their actions at a specific battle they will get a huge power boost over their regular forms. This is even the case with Lu Bu; compare him at Hu Lao Gate to say Guan Du or the Imperial Seal and you'll notice a huge power difference.
 * Particularly bad in Castlevania III when you must fight two of you possible allies - - before they join your party. Not only do they take more hits and do more damage when you fight them, but they're significantly larger in size as well.
 * Justified in the case of as he's been turned into a ghoul when you fight him.
 * Averted, however, in Order of Ecclesia. is one of the few enemies in the game Shanoa doesn't receive Collision Damage from, and when you unlock his mode, he can still perform every attack he used in your boss battle and deals a lot of damage and can also teleport at will, allowing you to breeze very quickly through the early levels.
 * Also averted in Symphony of the Night with Richter. Like Albus in Ecclesia, when you unlock his mode, he is a killing machine that breezes through the game at high speed, with as much or more power than he displays when you fight him in the normal game.
 * Partial exception: Destiny of an Emperor allows the player to recruit bosses at their full strength. However, since the main PCs gain soldiers (the game's equivalent of HP) over the course of the game and the bosses (and less important allies) don't, the bosses-turned-allies eventually become worthless. Except Zhou Yu.
 * Justified by in ~Baldur's Gate~ II: Throne of Bhaal. When he finally does join your party after having previously opposed you he has lost all of his Bhaalspawn gifts and equipment in the meantime (, not to mention that his experience has been static ever since and allowed you to close the level gap between you as well. He is still the best fighter NPC in the game despite this.
 * Kanon in Wild Arms 2 goes from being an extremely dangerous recurring boss to one of your weaker party members when she switches sides. There is no explanation for this whatsoever.
 * Bullshit, the last time you fight her, it's shown to have taken a heavy toll on her artificial body. Right after that, your first taste of her as an ally is in a fight against Judecca, one of the Quirky Miniboss Squad to the Big Bad, who is a tough fight even for the WHOLE TEAM when you fight him later. Kanon barely survives the fight against him. She thus pushed herself over her limits twiceover in a VERY short amount of time, and Marivel (who was busy trying to fix her before Judecca's attack) even notes the busted circuitry. Kanon noticed she had grown weaker, herself. ALL Of Kanon's abilities can be obtained with proper Level Grinding a Luck Based Mission.
 * She's the fastest character in the team and JUST as strong as Brad, the teams tank. Brad only stay useful at that point because of his dual-ARM limit break.
 * And, ya know, his oodles and oodles of hit points. Kanon is only useful later because she has a flat damage output that rivals Ashley's.
 * Lampshaded and mercilessly parodied in the Affectionate Parody game ~Jay's Journey~, where after the player defeats Shade the Ninja, Shade and Jay realize that they're actually on the same side. Upon joining the heroes' team, Shade loses a ton of hit points, can no longer cast the Dark 2 spell, and drops one sword, causing Jay to gripe. Shade can eventually get the spell and second weapon back, but those boss-level HP are gone for good.
 * Averted with Final Fantasy Tactics. The game features two Heel Face Turns, Marach and Meliadoul. Meliadoul joins your party late in the game, is appropriately-leveled, has most of her base job techniques already learned, and is equipped with some rather powerful items such as the Save the Queen knight sword. Marach on the other hand was just as crappy as a villain as he is as a hero.
 * The inverse also happens. Delita, Argath, and Gafgarion get Betrayal Promotions and become more powerful after they Face Heel Turn, Delita especially.
 * Perfectly justified in the case of Argath and Gafgarion, as their increase in power is simply due to level and equipment progression that is somewhat expected over time. Though one has to wonder how much Level Grind Argath went through in a short amount of time to go from being a near joke to the fairly challenging opponent he was. Delita, on the other hand gains a completely different default job class which could probably be explained by him going through special training or somesuch during the Time Skip, but how much more powerful he becomes on the battlefield is overshadowed by how much more dangerous he becomes in the political minefield the game is set in.
 * The thing with Final Fantasy Tactics is that in general, aside from character-specific classes, enemy units and your units work off the same damage formulas, and generally the mooks are only weaker than your units because their ability repertoire is not as developed. Therefore, Heel Face Turn or Face Heel Turn, there's no need for transition of stats to make adjustments.
 * Final Fantasy Tactics a 2 does this with when she is brainwashed by the Big Bad.  leaves the clan at one point and when that character gets brainwashed, their level skyrockets to 44 (or levels down if you spent a lot of time Level Grinding) and they have some awesome equipment. When you get them back, they revert back to the level they was before they left you, goes back to the job you were raising them has, and all the items she they in the battle are not kept. Subverted in that not only the job and power she had during this fight becames available few time after she came back, but she also gets more of them, gradually turning her into something close to a Game Breaker.
 * Fighting and beating Al-Cid plays this trope straight. Al-Cid is a pretty strong opponent, but when he joins your party, he comes in several levels lower than he was when you fought him previously.
 * There are several missions where the leaders of Duelhorn, Marquis and Alyss, join you a few times as a guest unit. When you face against them, they are quite powerful and dangerous. When they join your side for a while, they simply don't use their powers and opt to just stick to melee attacks or use abilities that are useless. However, when you fight against them afterwards, they go back to being powerful.
 * Some versions of Final Fantasy IV did this unintentionally. When Cecil converts from a Dark Knight to a Paladin, he has to fight Dark Knight Cecil as a Paladin. The Dark Knight Cecil uses Dark Wave every turn, but that attack was removed from the Easytype version (which was also the version that was released as Final Fantasy II on the Super Nintendo in the US), leading players of those versions to wonder why Dark Knights could shoot energy beams all of a sudden.
 * Cecil also goes down to Level 1 as a Paladin, but starts with around 600 HP and quickly gains levels and statistic points.
 * Speaking of Final Fantasy IV: When he's evil, Golbez takes a Meteor to the face and shrugs it off, can almost one-shot Cecil's entire party, and manages to regenerate his entire body from just a hand. After his Heel Face Turn, he's left with just 2,943 HP. His HP actually goes up in Final Fantasy IV the After Years, seemingly subverting this... but, in the process, he goes from over 500 MP to only 230.
 * Justified In The World Ends With You when decides to joins Neku's side after all other options of Neku's survival was destoryed. As a consequence he was kicked out of the, simultaneously losing all of the power that made him near impossible to beat.
 * An extremely egregious example in Final Fantasy V: when you fight the summon Carbuncle, he is a huge gorilla-like beast with terrible fangs, deadly attacks and a vicious temper. You beat him, gain the power to summon him, and when you're ready to use him to thrash over your enemies... you discover that he's turned into a tiny green mouthless squirrel thing that can only cast support magic. And he will continue like that for the rest of the series.
 * Averted in Paper Mario the Thousand Year Door- can actually become much more powerful after joining your party.
 * Despite this, oddly enough, she starts out without her move she used on you when she fought you until you go back to town to upgrade her.
 * Mostly averted in Luminous Arc (both games, I believe). Boss characters are simply a few levels higher and better equipped than you, but keep their stats, and equipment (which is genereally on par with yours by the time they join). However any characther who could summon monsters won't be able to do so when they switch sides.
 * Inverted in Overlord II with Queen Fay. In her appearances as a good guy she possesses magical powers such as teleportation, but shows no magic whatsoever after becoming your mistress following her Face Heel Turn. Justified in that turning evil was a side effect of you draining her powers to recharge your Tower Heart.
 * Not only that, but the Tower Heart has also consumed every drop of magic in the entire Sanctuary, so that by the time Fay is converted she's literally out of juice.
 * Ace Combat Zero, where ADFX-02 Morgan has all three special weapons equipped without needing to RTB to change, albeit in phases, and has a far more potent ECM system than Cipher's ADFX-01 copy has. Also Ace Combat 6, where Ilya Pasternak's usage of the CFA-44 Nosferatu comes with a bunch of attendant drones, whereas Talisman's doesn't. In X, the playable Fenrir lacks the High Powered Microwave Cannon and Digital Optic Stealth of the enemy versions, though there's a throwaway line or two about being incomplete.
 * Played to a T in Shining Force 2. Jaro joins you mid-battle...and loses stats because he was tired of working for the Devils.
 * Yuffie in Final Fantasy VII has several unique and powerful attacks when you first encounter her, but upon joining your party she loses those abilities and becomes a normal character.
 * However she'll eventually become far more powerful in your party than her random encounter version ever was anyway.
 * Subverted in Final Fantasy X with the Aeon Anima. When you first see her, she's being summoned by Seymour and she proceeds to utterly annihilate a passel of fiends infesting the city of Luca--fiends your party itself had been fighting earlier--in an apparent display of Cutscene Power to The Max. Later, in the first boss fight against, he'll summon her and, while she's no pushover, she's a far cry from the engine of destruction she was at Luca. Lastly, much, much, much later in the game, you're allowed to obtain Anima as your own summon, and, well...Can you say Game Breaker? She's obscenely powerful, naturally breaks the damage limit, and has balanced stats and no fiddly mechanics like the other overpowered Aeons have. Taking her back to Luca to fight fiends identical to the ones that invaded so long ago will reveal that, no, that was not Cutscene Power to The Max, she really can rip through them like a woodchipper with balsa. It's very surprising, and also supremely confusing when one remembers that Anima is
 * Inverted in the game with Seymour himself to a degree; a while after you see him shredding all of those fiends with Anima, he'll join your party for a single bossfight. While very powerful, more so than your characters will be at this stage, he can't summon Anima and isn't nearly as powerful as when
 * In Final Fantasy XII, a Guest Star Party Member pulls a Face Heel Turn on your party at one point and is much more powerful and durable when you face him in an inevitable boss fight than he was when he was on your side. However, other than gaining passive abilities when he Turns Red, he doesn't pull anything you haven't seen before. All of his attacks are the same ones he had when he was helping you, they just do significantly more damage.
 * There is also Judge Gabranth, The Dragon to Vayne for much of the game, who pulls a Heel Face Turn and assists your party during one portion of the Final Boss fight against Vayne. His health and strength levels are significantly lower when he's helping you than they were during the two boss fights when he fought against you earlier in the game. Justified, though, as the second boss fight against him happens only a few minutes earlier. So when he comes to your aid, he's still weakened from the beating he just received by your hand.
 * The Espers also bear mentioning, particularly the optional ones that the player does not automatically receive during the main storyline, who are among some of the toughest boss fights in the game. After you beat them, they become available as summonable allies. While they are fairly powerful when summoned, it is nowhere near the degree that they were during the boss fights.
 * of Last Scenario had the ability to summon a troublesome boss, appear and disappear at the most convenient of times (passing through unwalkable tiles), and could even deal quite a bit of damage when you finally fight her. She was already a competent soldier when two of the main characters were just little children. And then she joins your party...
 * Twisted Metal: The playable versions of Minion in every incarnation are about half the size, have no force fields, lower life, weaker weapons, etc.
 * Every Touhou game, without exception, in which player characters only have access to a small number of their available Spell Cards, which are also drastically reduced in both power and duration compared to when they were antagonists. By far the worst is the eighth game Imperishable Night, in which not only were six of the available characters fought previously, two of whom being the Final Boss of the preceding two games, but the fourth boss is one of those available characters, who is naturally far stronger than when the player uses her.
 * Also inverted in the PC-98 games: Mima is one of the most lackluster final bosses in the series. Once playable, though? She has THE best shot type of all in Mystic Square
 * And an exception is Phantasmagoria of Flower View, due to the symmetric split-screen mechanic; you're a boss character to your opponent's "player character", and they're a boss to you. While the AI doesn't behave identically, the characters do. The regular games are more a case of mechanic asymmetry; the "boss version's" hit points are traded for mobility and evasion, and the variety of spell cards are replaced by supercharged regular attacks and a couple of equally upgraded cards (you can theoretically dodge any boss's attack or spell card; they generally can't avoid any of yours).
 * The fighting game Immaterial and Missing Power, however, plays this trope straight for any character you have to unlock, as most of the challenge in the single-player story mode is learning how to dodge and shut down the various unlimited-duration, amped-up spell cards the AI characters invoke and spam between bouts of regular fighting.
 * In Persona 4, Personas are created out of Shadows when the person in question accepts their "true self". While the transformation makes the spiritual entity loyal and controllable, it also decreases their stamina at least a hundredfold, eliminates all their cool attacks, reduces them in physical size, and decreases their attack power. This is justified by Teddie's explanation that a strong-willed Shadow draws others to it to form a big mass of Shadows, and they make up the form you fight in the boss battle. So you're really fighting several Shadows combined in the boss battle, whereas when the character gets his Persona, it's only made up of a single Shadow.
 * In  ~Mario and Luigi: Bowser's Inside Story~ , this happens in the middle of the game. Bowser, who you had previously been controlling, fights the Mario Bros as a boss. He has increased HP, increased Attack, and the ability to target both brothers with a move which normally targets one opponent. Justified, however, in that you're the Mario Bros, and thus can dodge his attacks (and counter back) while most enemies cannot dodge his attacks.
 * While taming in World of Warcraft is not exactly a Heel Face Turn, upon becoming a hunter pet, the tamed beast immediately shrinks in size and loses any special abilities it had, reverting to the generic name (e.g. "Cat") and generic abilities of its species. At least it retains its appearance, prompting hunters to search the wilderness for more unique-looking mobs.
 * This actually doesn't count--while the pet may lose any special skills and their name, their actual stats go through the roof, not to mention their level if you went back to an old zone for one.
 * Another note: In regards to the pet's level-- it is possible, with a particular talent, to tame "The Beast" in the instance Leeroy Jenkins made famous. The Beast's level is...?? (boss). Upon taming it, it will lose most of its HP (In the wild, this beastie has ~86K, the most you'll ever see a Hunter Pet have is 35K-ish with high end Pv P gear.) and a lot of its attack power, but gain the Talent Points for Your Level -5, and acts as any other Core Hound... however, it retains its displayed level (?? (Boss))...RuleOfCool, much?
 * Pokémon Mystery Dungeon has this with pretty much every legendary you can recruit.
 * By hacking the data it is possible to see that you actually get a copy of the recruitable boss upon defeating it. The boss version has higher stats in all areas, but most notably HP. They have 500 to 900% more HP than the playable copy you get.
 * Common recruitable pokémon also suffer this: as enemies they have 300 to 600 IQ points, but once recruited they lose all the IQ points and all the IQ skills learned.
 * Inverted in the Half Life series. The Vortigaunts, a race of lowly mooks in the original, became friendly once Half Life 2 and its subsequent episodes rolled around. However, it wasn't until Episode 2 was released that we saw the inversion. Here, a team of 3 Vorts
 * Although the guys they were fighting in the first game had guns. Antlions don't have guns.
 * Although they did show a remarkable affinity for machinery that they didn't previously possess as far back as Half Life 2
 * Chrono Cross has several examples, due to the incredibly huge number of characters you can recruit. Probably the biggest example is Grobyc. As a boss, he has thousands of hit points and attacks that can annihilate your entire party repeatedly. Afterwards, he has the usual 400 or so HP and can no longer use the oh-so-broken Vigora.
 * Xenogears. When you first meet Rico, you have to fight him in the arena and he does 5 digit damage to you per attack (an instant kill a hundred times over). When he joins you, he turns out to be pretty pedestrian.
 * Inverted example in Exit Fate: when you defeat Vanrushal the vampire, the damage drains his power and leaves him on a "mere" human level. Since he finds you interesting and, more importantly, cannot stay at his monster-filled mansion like this, he joins your army instead. In other words, his demotion causes him to join you, not the other way around.
 * Katt in Breath of Fire II takes a considerable beating when you first encounter her. After joining up with you, she is quickly demoted to Fragile Speedster status.
 * Inverted and played normally in Baten Kaitos over the course of a single battle: one of your party members pretends to switch sides in order to get the rest of the party to "test your strength," rejoining the party after that battle. The party member has 3300 hit points during this battle. Now, the mechanics of the game are such that bosses don't have all that many more HP than the party members (the ratio is more like 3:1 rather than 20:1), and this party member will actually reach 3300+ HP in the course of the game (assuming you level her up), but at the time when this pitched battle occurs, it's still more than the high-three-digit HP values your party will probably have at that point in the story.
 * Justified in Neverwinter Nights 2: by the point joins you, he has just been stripped of his incredible power as a result of  freeing the bound demons that powered him.
 * Inverted in the first two ((X-COM)) games. Your mooks are inaccurate (even with training) and stupid... but when they get their brains sucked out and replaced with green alien goo they become much more capable, accurate and dangerous. "Durrr, I'm shooting at something I can't even see on the other side of a bookshelf, and ignoring the thing sneaking up on me." (wet slurping noises) "Boom Headshot! Boom Headshot! Boom Headshot!"
 * Lampshaded in Cthulhu Saves the World, where Sharp's in-combat description is "Has a much higher max HP now than he will in a couple minutes." Also inverted, as he initially sees Cthulhu as the villain (With good reason).
 * In Sonny, Felicity is an early-game boss battle, with 2500 HP. When she joins you at end game, she has... 2500 HP. Which wouldn't seem too bad, except you and your enemies will probably be doing about 1500 damage per hit, not counting special attacks, making her an ultra-brittle Glass Cannon.
 * Subverted and then inverted in Venus Blood saga, especially in it's newest instalment, not only any character that joins you won't be any weaker than as an enemy, but if you decide to corrupt the heroines, they'll become much powerful.
 * And then there is VB: Frontier, where in the evil route you can corrupt them further, and the power up will be even greater, at the cost of sacrificing their abilities. Justified since the heroines either lose their sanity, or their bodies change and they can't keep fighting like they used to.

Web Comics

 * When Gwynn first started learning magic in Sluggy Freelance, she was able to throw around spells like nobody's business in her quest to get payback on Riff. When she realizes she was wrong and tries to be a good person, she uses magic much less frequently. Justified since her powers come from the "Book of E-Ville."
 * In Dungeon Crawl Inc, hot drow cleric Teagan loses her magic powers after falling in love with Castor and siding with the heroes.
 * In Double-U Tea F, Raike goes from the Big Bad/Ganon of the series (Capable of taking on most of the heroes at once), to being one of the less effective heroes after his Heel Face Turn and subsequent name change. However, looking back at his earlier appearances shows that when he isn't using Chaos Corruption, he has about the same level of power as his (Heroic) brothers, and may actually be slightly weaker (Understandable, given that he's the youngest of the three). It's just hard to notice due to the fact that he has precisely one fight scene where he doesn't use Chaos Corruption, and there's enough of a power gap between him and his opponents that he seems super strong by comparison. Not helping matters is the fact his final appearance before his Heel Face Turn featured him, which made his subsequent fight scenes make him look even weaker by comparison.

Western Animation
"Zuko: I bet it's because I changed sides."
 * Zuko lampshades this in Avatar: The Last Airbender when he joins the Gaang and briefly loses his Firebending, which he attributes to his lack of inner drive, which was previously capturing Aang, and general rage (he eventually improves over the course of the episode).


 * Scavenger in Transformers Armada was initially a quite a big threat, until he became an Autobot and started taking a lot of naps.
 * Exception: Dinobot of Transformers: Beast Wars started as a bad guy Predacon, but joined the Maximal good guys in the second episode. As a villain he was good but not overwhelmingly powerful, and after joining the Maximals he remained one of their most effective warriors up until his death. And he died fighting against every Predacon warrior in the series at that point in rapid succession, to boot!
 * From the same series, though, Blackarachnia was notably less effective as a Maximal than she was as a Predacon, though more because of inner emotional distress than any explicit depowering.
 * A justified example; after his Heel Face Turn to the side of good on Gargoyles, David Xanatos laments that he's not as pro-active as he was when a villain, being limited to reacting to threats rather than causing them. He does, however, remain frighteningly competent.
 * In the Rankin-Bass holiday special Santa Claus Is Comin to Town, the Winter Warlock appears as a villain with massive powers of weather control. After Kris Kringle uses The Power of Friendship to melt his icy heart, he later sadly explains his powers are now limited to a few novelty gimmicks (such as corn that makes reindeer fly).
 * In The Batman, the original Clayface, Ethan Bennett turns good and goes fighting a new clayface who has the exact same powers. Despite having three more years to practice with his powers, Bennett still loses miserably to the new clayface, who just got his power a few days ago.
 * This had more to do with the new Clayface taking an ass-load more of the clay that mutated them than Bennett as he became infected intentionally. Also, unlike Bennett, Karlo didn't have to worry about losing control because he didn't care.
 * Ben 10's Evil Counterpart Kevin 11 seems to be going through both this and The Worf Effect following his mid-series Heel Face Turn between Ben 10 and Ben 10 Alien Force. Justified since he refuses to absorb energy again, which was what made him a dangerous threat in the original series. In Ben 10 Ultimate Alien Kevin reveals that absorbing energy like electricity or the Omnitrix's power will drive Osmosians like himself and Aggregor insane.
 * Mark Chang on The Fairly Odd Parents is the prince of the most feared planet in the galaxy, which is very apparent in his early appearances. Then, after his Heel Face Turn, he seems totally unable to fight Princess Mandie.
 * When opposing them, Amazo from Justice League was the most powerful being ever introduced who could brush off every superhero in existence with minimal effort. He fought against Solomon Grundy on the JL's side, lost, and simply left.
 * Amazo didn't necessarily lose, He attacked Grundy with the intention of simply erasing him from existence, when his attack seemed to empower grundy he stopped, and concluding that his attacking him again might be dangerous retreated several light-years to come up with a new strategy. He was still thinking about what to do when the episode ended.
 * An interesting variant: in Kim Possible, any time Kim's Sidekick Ron is turned evil (through Applied Phlebotinum each time), he's suddenly just as much a cackling Mad Scientist as Drakken, only to go back to his usual self as soon as the process is reversed (which, naturally, always happens by the end of the episode).
 * "As much as" is something of an understatement. He turns out to be far more effective than Drakken, to the point of actually intimidating Shego into backing down.
 * In the Battle Tech cartoon, Ciro Ramirez is a passionate, competant, but also arrogant and inexperienced Mech Jockey serving under Adam Steiner in the 1st Somerset Strikers. He experienced a reversed form of the trope after his Face Heel Turn, Justified in that the Clans have better technology, more experience, and presumably gave him the sort of training that the Clans are known for.
 * Who could forget Dark Heart from Care Bears? Before the Heel Face Turn, he was a bad ass shape shifter. Some Power of Love and Clap Your Hands If You Believe later, he's a weak human with no powers. Becoming a real boy is overrated.
 * Hexadecimal from Re Boot. As a virus, she is the queen of chaos. As a sprite, she can't even fly. To save the system from the supervirus Daemon, she must power back up-which drives her right back into total insanity.
 * Tohru in Jackie Chan Adventures. In Season 1, he's The Brute among the villains and very much a Mighty Glacier who routinely tosses Jackie around like a ragdoll during fight scenes. At the beginning of Season 2, he pulls an abrupt Heel Face Turn and becomes a Gentle Giant. Though he can still hold his own in a fight when needed and is always The Big Guy when teamed with Jackie and/or one of Jackie's other allies, these are few and far between and he's typically not portrayed as the overwhelming powerhouse that he was as a villain in Season 1.
 * at the end of Care Bears Movie II: A New Generation, thus losing his powers, but seemingly couldn't do any real human things until now.