One Man Party

A (typically) RPG and SRPG Trope, wherein the engine allows a single character to become vastly stronger than the rest of the team, but then either not be punished for this, or the punishment fails to counteract the practice. An alternate form of this Trope is a game that allows characters to fall through the cracks and become vastly weaker than the rest of the team, and require special effort to fix.

Frequently these games only award XP for characters who actively participate in battle, meaning that the powerhouse is the only one gaining experience after an early lucky break. Alternately, some RPGs and SRPGs randomly give out skills or stat increases, which accomplishes much the same thing. The powerhouse, due to the quirk of the engine, typically becomes an invincible, instant killing monster long before the experience curve cuts them off, leaving them on an entirely different playing field than their teammates and the NPCs.

This is often cyclic, with one character becoming slightly stronger, making it more likely for them to land the finishing blow, or survive the boss's attacks, leading to them gaining more levels and strength, making it easier for them to kill the enemies and survive and so on...

In some instances the game will attempt to fix this by lowering the experience given by killing monsters if your character is too overpowered compared to them. This just causes plateaus to occur during the leveling process as the character instant kills enemies, but doesn't gain anything from it until later maps are unlocked.

This tends to happen to the main character of a game, especially if he can't be removed from the party. As a consequence, since you may be switching in and out other party members to suit the situation, the main character may very well be several levels ahead of everyone else. Can be particularly jarring when you have to specifically avoid doing this, by simply avoiding using your heavy hitters so the rest of the party can gain experience.

Some RPG players take advantage of this trope in order to do a Solo Character Run, a variety of Self-Imposed Challenge that has the player go through a game using only one character out of an entire party.

In recent years, this trope has been intentionally invoked by Fighting Game makers as a form of balance -- by placing a character that is intentionally overpowered in a team-based game, but balancing this by making the overpowered character take up multiple character slots, the equilibrium is maintained. The overpowered character may be very strong, but any opponents will have multiple tries at defeating him. Interestingly, this is the typical way bosses are balanced in these types of fighting games.

A subtrope of Game Breaker. For the storyline version of this, see Can't Catch Up, One-Man Army. For a character that appears to be a One Man Party but is later Put On a Bus, see Crutch Character. For the more overreaching version that covers play styles or balance issues, see Unstable Equilibrium.

Fighting Game

 * Most boss encounters in games with multiple characters per side invoke this trope -- the boss will be vastly more powerful than the player, but the player will have 2-3 characters to make up for it.
 * Skullgirls has a variation in the form of the Ratio System. Each player, instead of being forced to select three characters for a full team, can either select one, two, or three, and the game adjusts damage and health accordingly. So if Player A chooses only one character while Player B uses three, Player A will have much more health and damage, but won't have access to assists or extra characters.
 * Capcom Vs SNK 2 previously used a Ratio System to govern its battles; players had access to a total of four points, with a maximum team size of three, and characters were handicapped in terms of offense and defense in accordance to the Ratio assigned them. Thus you could have a split of 2-1-1, 2-2, 3-1, or 4. Boss fights were always against one opponent at Ratio 4.
 * In Marvel Super Heroes vs. Street Fighter, Cyber-Akuma is a secret character in the console versions. Unlike everyone else, who you need to take as half of a pair, he has to be used alone. Given that he is the arcade mode-ending SNK Boss, with all the power that implies, it is justifiable.
 * This continues in Tatsunokovs Capcom with the humongous mechas, Gold Lightan and PTX-40. The two are both astoundingly powerful alone, so they play through matches without a partner.
 * In Capcom vs. SNK 2, you had 4 team slots that you could allocate however you wanted. You could put all four slots on one character, creating a single, high-powered team member.

Real Time Strategy

 * A properly built Cyrus in Dawn of War 2 is capable of soloing entire maps, though this requires a lot of player skill.

Role Playing Game

 * In MARDEK, the titular character becomes this in Chapter 3, due to the fact that you can't take him out of the party.
 * Most entries in the SaGa series of games by Square Soft drop a straight leveling system in lieu of stat based skillups that are capped based on the strength of enemies you are fighting. Fighting fast Werewolves will increase speed and agility, for example, while smacking down Golems will increase defense and health. The problem becomes when characters are switched out -- the new characters will gain stats very FAST from the monsters the rest of the party can survive... but only if they live through combat (and get a hit in, or get hit and live!). That's a big if in the later areas, when, for example, a random Waitress or out of work Bum joins your party.
 * Another version of this trope occurs in the skill system in the Saga series. Using weapons, spells, or getting hit and surviving can cause a character to randomly learn a skill. If a character gains a sufficiently deadly skill, this trope is instantly invoked -- the character suddenly can get more hits and killing blows in, survive more attacks, etc, leading towards a huge jump in ability. The small name massive crossover SRPG Chaos Wars used a similar skill system with similar problems.
 * Final Fantasy Crystal Chronicles: My Life as a King suffers from this a bit, as the difficulty level of the dungeons goes up quite fast, and any weaker characters tend to get left in the dust.
 * Not to mention the fact that whoever completes any behest that involves killing a boss (ie. most of them that aren't just "explore location x") is awarded a medal that either changes one of their AI traits or increases their base stats by a varying amount depending on the relative difficulty of the boss they killed. Since the stat-boosting medals are available in unlimited quantity, the stronger the character, the more likely they are to kill the boss and because all the medals are awarded only to the party leader, this is a far bigger factor in making a single character stupidly overpowered.
 * The first game can be an example of this if you don't have a spare GBA or two for multiplayer
 * Final Fantasy VIII unintentionally subverts this -- the enemy's power levels are based on the main character's level -- so most people wanting to Munchkin their way through the game leave the main character dead when leveling up the rest of the party. It is best not to do this too early in the game, however, as your stat growth is dependent on what summon you have equipped.
 * In Final Fantasy IX, the main character Zidane eventually does orders of magnitude more damage with his standard attacks and is much faster than Steiner(without his secret weapons) or Freya. Vivi can eventually outmatch him once he gets Doublecast, but at the cost of ludicrous amounts of MP.
 * Unless Freya has her Dragon's Crest ability and the party has killed enough dragons, in which case she winds up dealing 9999 damage every turn, regardless of enemy defence, for a paltry MP cost.
 * In Kingdom Hearts, Sora gains experience at the same rate and at times is a lower level than Goofy. However, he gains more abilities to fight with, can use all the spells Donald can and has stronger weaponry than either. The reason for adding Limit Attacks in the sequel was to actually give a purpose and need to different party characters.
 * Name a Monsters game, any Monsters game. This trope could also be named Alakazam Syndrome, for example, due to the first Pokémon game's vastly overpowered Psychic Pokemon -- a valid single-player play style is to use one Pokemon exclusively, until he is dozens of levels higher than anyone else. Later games avert this to a degree by fixing the Elemental Rock-Paper-Scissors system, although a strong enough Pokemon can still ignore this, especially if they have a sucker punch in the form of an attack that targets the things they're weak against (A Fire Pokemon with a Grass or Electric move, for example, to kill off any Water Pokemon before they can attack).
 * Truly experienced Pokemon players pick a Mons to do this with that will sucker punch the rival's Pokemon -- for example, starting with fire, letting the rival pick water, then powering through the game with a grass Pokemon instead, combining One Man Party, Elemental Rock-Paper-Scissors, and a Out Gambitted all together. In modern games, there are also a few new types of Pokemon -- Dark and Steel -- which are oddball enough to avoid most of the Elemental Rock-Paper-Scissors nonsense as well.
 * Not really. When it comes to beating the game with a one mon army, there are only two things that matter: they should not be weak to the stronger Elite 4 pokemon - as in, able to survive a few hits - and have a movepool diverse enough so you can hit almost everything by neutral damage.
 * In the earlier Pokemon generations, it was entirely feasible to beat the game using only a single Pokemon (plus "HM slaves") in the first playthrough, particularly if you were young, had little RPG experience, and/or were not very interested in the tedium of equally leveling your mons.
 * You still can. Infernape in particular has a wide movepool and could devastate the entire game easily.
 * In all the generations the Water starter can obliterate the game with ease if you train him alone just by beating all the trainers around. They have balanced stats, have a wide movepool that allows them to hit grass-types for double damage and at least neutral on everything else, and have only two weaknesses, electrics who are damn frail and grass, wich are owned by Ice Beam, an attack that all the water starters can learn.
 * There are also a few ways to level up Mons outside of battle, but they'll still end up weaker than ones who leveled up via battle.
 * Pokémon Black and White mostly averts this -- your experience gain is modified by your level delta compared to the target monster. Monsters that have fallen behind catch up very quickly, monsters that are far out ahead are effectively wasting experience.
 * Persona 3 and Shin Megami Tensei games avoid this, as your monsters and Persona level up very slowly compared to your main character, who can just summon stronger ones as needed. Certain monsters do stick around, for example the ones based on Deities or with special attacks or immunities, but are quickly outclassed by the other monsters due to sheer levels.
 * But it also plays it straight in that, for example, your party healer has a high likelihood of never leaving the team, and so winding up being second only to the main character in experience points. Doubly so if your healer has one of the "Growth" abilities, allowing them to gain XP even when not in active combat.
 * Allies who are significantly lower in level than the protagonist gain XP much faster than normal, so it's not too tough to make them competitive again if, say, you need to swap someone out due to their elemental weakness against a bosses attacks
 * Nocturne plays this straight with the Fiend class of demons. You need to beat some powerful bosses and collect some rare items from the bonus dungeon before you can summon them, but they're well worth it. Thanks to their ridiculous resistances and special abilities, these demons tend to stick around FAR longer than anyone else you can recruit.
 * The "healer" Fiend, an undead Buddha, takes this beyond normal -- by having a passive skill that gives him XP even when he's not being used. Once you get him, he stays in your party, no matter what game you have him in.
 * Of course, a far more obvious application of this trope in Persona 3 is the main character himself. The simple fact that he's the only character capable of using multiple personae makes him FAR more powerful than any other character, largely because none of the other have access to more than one elemental attack (and some have none). Even more ridiculous if you start a New Game + game, where he retains his level from the previous play through as well as all his top-end equipment and access to all the powerful personae he had in his Persona Compendium. He can literally smash any monster in the first half of the game in 1 blow.
 * Averted in Persona 4, where the main character doesn't keep his levels. (He does, however, keep the Compendium, his money, and his social stats, which erases a lot of the scrambling around from the first playthrough.)
 * Likewise, played straight in the original Persona, as characters gain EXP based on how useful they were in the fight. The strong get stronger, and the weak fall further and further behind.
 * There's something to be said about Persona 2 when the favored strategy for beating Innocent Sin's final boss is to have Tatsuya solo it until it's weakened to a point where you can have Maya use Recarm-Dora on the rest of the party to finish him off...
 * Neverwinter Nights allows you to custom build your main character, which opens up some very interesting possibilities. So called "Epic Builds" tweak the rules in such a way that your main character will maximize whatever power he can possibly use (often with loopholes and weird combinations of skills). NPC Party Members, mere single or duo classed slobs, will be left far, far in the dust, essentially delegated to support roles.
 * Wasteland had an odd version of this. In normal melee combat, turn order was determined, somewhat randomly, which did give a decent chance of kills to trickle down. However, since it's After the End, most combat is with guns. And gun combat is ALWAYS from the 'front' to the 'back' of the party. So shots will always go 1-2-3-4, even if 3 is a squirrel on speed, 4 is a ninja, and 1's barely faster than the cacti.
 * In Valkyrie Profile, Lenneth is required to be in every single battle you fight (except one in the best ending), and there's Loads and Loads of Characters. By the end of the game, Lenneth will invariably be at least a dozen or so levels ahead of anyone else in her party.
 * Probably justified, since she's a goddess, and most of the rest of the party are heroic ghosts.
 * Each game's Valkyrie is the source of DME (Life Force) for her entire party and her companions will quickly dissipate if she isn't on the field.
 * A modified version of this comes up in Silmeria, as by the endgame, one optimally-equipped person has a much higher chance of slaying enemies alone and outnumbered than with a full party with similar equipment. Dylan, for example, when alone and properly equipped, can take out seven levels of the Seraphic Gate without any special buffs (such as Fencer's Familiarities, which increase a stat). Also, with the exceptions of Alicia and Rufus, every other main character is gone from the party at some point, and most do not return until the bonus dungeon.
 * In Earthbound, Ness, whom you've had all game long anyway, and who additionally gets special stat boosts (including LOTS more PP) late in the game, becomes a powerhouse at the end--and while he doesn't have the most efficient damaging attacks (Paula and Jeff take care of that), he has tons of defensive and healing spells and enough PP to spam-cast some of them, and he also has enough HP to last through a lot of attacks, and thus becomes the party's one-boy backup. Not to mention that, even if not efficient, he does have some nastily damaging attacks himself. (It doesn't help that Paula and Jeff start at level 1. Poo starts at level 15, but you're probably way overleveled even compared to that when you get him.)
 * This gets really nasty at end game where normal enemies can insta kill Paula, rendering her offensive skills moot.
 * Ness's power boost depends on two factors, not being at too high a level, since the new system rewrites future levelling to much more substantial, and non killing off too many of the Flying Mans (since you pretty much end up racking up huge amounts of experience in the process through repeated trials, and also it probably does something to ability growth). This is the result of playing two different games, the second with heavy grinding and killing off Flying Man, and the first with low levels and and beating the Magicant boss with no Flying Man used. The death of Flying Man seemed to accelerate level speed, but the difference was something like 300 hp at level 90.
 * In the Star Wars: Knights of the Old Republic games, the player character is forced to be by his or herself numerous times, and they wind up learning combinations of abilities that the others can't learn and don't even fight the final boss with them.
 * And in the second game...the player character even gets their own PRESTIGE CLASS. Sith Lord and Jedi Weapons Master wind up outclassing all the other characters, many of which become jedi.
 * However, everyone gets full XP, even if they're not in the party, so all the levels end up the same anyway. (When it becomes a problem is when you've realized you've only upgraded your PC's weapons and armor, and have cruddy equipment for the rest of your party.)
 * Fallout games have frequently suffered from this, even more so in the modern FPS-based versions - sure, you can take on that pack of Deathclaws, but is anyone else in your party really going to survive?
 * Since party members are Killed Off for Real when they die, solo adventuring is practically mandatory in the deadlier zones if you feel any affection at all for your companions.
 * Companions can actually make you less effective in combat, usually by getting themselves detected while the player tries to sneak around, and forcing the player to be much more careful with splash damage weapons. Of course, lower level, or less skilled players may still get some mileage out of them--until either the player or his character get their acts together, at least.
 * The companion control interface in Fallout 2 actually lampshades the party members' tendency to shoot the player in the back in the previous game. When giving the NPC instructions on when to use burst fire, the safest option is "Be Absolutely Sure You Won't Hit Me."
 * Fallout New Vegas rewards the player for having a follower or two (the Arbitrary Headcount Limit restricts you to 1 humanoid and 1 non-humanoid, however), which each follower bestowing a "Companion Perk" that helps you in some way (for example, letting you target cloaked enemies in V.A.T.S., slowing the rate of item degradation, or increasing the effectiveness of healing items). The Lonesome Road DLC adds the "Lonesome Road" Perk, which increases damage and V.A.T.S. accuracy, but only appears when you have no Companion Perks.
 * Suikoden tends to make sure this doesn't happen too badly. Your protagonist is always in battle and stays a few levels above the rest of the party, but the way the experience scales tends to make sure new additions, latecomers, and those who were gone for a while get up to speed soon enough, often gaining multiple levels per battle until they reach the appropriate ballpark. Given the series' propensity toward Loads and Loads of Characters, this is pretty much the only way they could have pulled it off.
 * Due to the party make-up mechanics in Final Fantasy IV, Cecil's transformation (and accompanying level reset) into a paladin was likely an attempt to avert this, as otherwise he'd likely get a dozen or so levels above the rest of the party without trying hard and stay there.
 * Inverted if you attempt to level him before the class change -- he won't be any stronger after the class change, but his experience count is never reset, and new (or rejoining) characters are leveled based on his XP. Yang can be powerful enough to one-shot entire fights with a single Kick.
 * In Soul Nomad and The World Eaters it is very easy -- almost too easy -- to turn Revya's unit into a One Unit Army by putting all your hero characters into it. Since all the other units have to be summoned onto the field and take time before you can act, hero characters are far superior to their mundane counterparts, and Revya's only real bad matchups are Gypsies and Gideons (the latter only show up in a Bonus Boss fight), this will allow you to almost finish the game with that unit alone, given a good room.
 * In Shadow Hearts the main character so dwarfs everyone else that the main discussion about what groups to use to fight the endgame bosses is limited to "Who is the best item caddy for Yuri?"
 * It's entirely possible to pull this off in Dragon Age Origins w/ the right character build. There's no real benefit though since you don't get any more exp this way -- the only real reason to do this is for the challenge. At least your other party members don't suffer for it thanks to Leaked Experience.
 * Crono of Chrono Trigger is the hero and party leader. He can't ever leave the party voluntarily, so every time you switch out characters he gets stronger in relation to his companions. It's not really a big deal: there are only eight "Techs" (abilities) for each character, and every character earns these techs at exactly the same level of work. Once you've maxed out the whole party (which you have probably done by the end of the game as a matter of course,) the whole point is moot. Even if you haven't maxed out everyone, the active party only holds three people and you're practically guaranteed to have three high-level badasses by then.
 * Of course, once he leaves the party involuntarily, it's pretty much anything goes. You can have him on the bench for the rest of the game and still make it through.
 * Generally averted in the Wild Arms series, as most of the time you don't pick your party members, though the Luck rune in Wild Arms 3 plays it straight as that character that equips it can get an ability that allows them to get more XP per battle than the others.
 * Raquel in Wild Arms 4 is the exception to the rule. She has superior attack strength and battlefield mobility than the other characters, and in Wild Arms 4 whichever character strikes the killing blow will gain additional experience points. The result is that Raquel will often power ahead of everyone else and not look back.
 * Dragon Quest III makes this easy as all party members other than the main character are optional and XP is split between party members instead of copied; you can reduce your party to just the hero and be earning 4x the "normal" XP, allowing the main character to level up enough that it doesn't matter that he's alone. A character of the Sage class can also be something of this, as they can cast both Priest and Wizard spells but with better weapons and armor than either of those classes.
 * Dragon Quest IX does the same, plus the XP split is weighted in favor of the stronger characters. If someone falls behind because their class needs more XP to level up than another guy's, they're not going to start catching up until the others start hitting the level cap.
 * Taken to its logical conclusion in Dragon Quest Monsters Joker 2 -- The game has a size ranking, you have a party limit of 3 units of size, and monsters are 1-3 units large. Size 3 monsters are literal one man parties, you cannot have anyone else if you are using them. But they're also only available in the post game and easily equal in power to full parties. There are also reasons to take the other combinations -- 3 size 1s will have more skills, and ultimately do more damage... if you can keep them all alive as they have 3 weaker targets to kill as opposed to 1 big target.
 * Averted in .hack//G.U where characters that aren't in your party can still gain levels after certain events have passed.
 * Actually averted for the most part in The Reconstruction, where is really the only character who can hold their own against all comers, since everyone else can only inflict two kinds (or even only one kind) of damage.  isn't really an example though, since his Soul attack is very difficult to use and he has terrible stats. There is one character who stands out, though: Santes. She's widely considered a Game Breaker, due to the fact that she has some really good healing spells as well as what is quite possibly the strongest direct damage spell in the entire game. However, she can't inflict Body damage, so she's kind of at a standstill if she's facing a high-Soul, low-Body opponent.
 * Qualstio becomes this late in the game once you get his semifinal passive ability, Stifling Heat. It raises the chance of one of his spells inflicting Disable to almost 100%. If he uses it every single turn, his victim will never be able to hurt him.

Strategy RPG

 * Zeorymer of Hades Project Zeorymer. In ANY Super Robot Wars game it appeared in, no matter the situation, the player could toss Zeorymer to the enemy's Zerg Rush and laugh. This is a game franchise filled to the brim with Godlike / Magical / Uber-powerful Robots including Evangelion, Rah Xephon, or even Ideon, and Zeorymer is STILL considered one of the standout Game Breaker and God Mode Sues in the SRW franchise. What a feat...
 * We haven't even gotten into the fact that Zeorymer in Super Robot Wars Judgment gets UPGRADED to Great Zeorymer, taking its game-breaking abilities Up to Eleven. To illustrate, its weakest two attacks are the ultimate attacks of three of the bosses it faced...
 * Many games by Nippon Ichi have a tendency towards this; only the character that strikes the final blow on an enemy will get experience points for killing it, so there's a tendency for strong characters to get stronger and for weaker characters to fall behind unless the player is deliberately trying to keep power levels balanced.
 * Prier, the main character of La Pucelle, could easily turn into one.
 * In Disgaea Hour of Darkness, Laharl is usually the character that ends up this way, although you can do it with almost anyone. Strategy for defeating
 * Parodied in Makai Kingdom. Zetta is beyond godlike, being a level 2000 monster in a game where the last boss is around level 80. Zetta is also a book and can't so much as move without outside help.
 * Phantom Brave goes to some lengths to try to avert this. Aside from main character Marona, who tends to have weak attack stats, all your characters can only stay on the battlefield for a certain number of turns, so if you try to rely on a single, powerful attacker to win fights, you'll fail. On the other hand, you can also improve your weapons in addition to your characters, so you could easily end up with a single Infinity Plus One... Fish that makes its wielder much stronger than anything else on the battlefield. (Of course, given that the enemies in the game can steal items from you, this can be a double edged fish, although there are precautions you can take to lower the chances of that happening.)
 * Ogre Battle has a system that causes an enemy squad to flee back to their base if their squad leaders are defeated, wherein they regen to full and charge right back into the fray. Ergo, if your defensive units can kill a squad leader but not the rest of the squad, they will gain a rather large amount of experience, rather quickly, as the squad plays ping-pong between your squad and it's base. The game attempts to fix this by causing higher level characters that beat weaker level enemies to slowly turn evil and lowers their charisma, which even evil classes need.
 * Tactics Ogre avoids this mostly by keeping the bell-curve very low and punishing you severely if you are surrounded (with permanent character death thrown in for good measure). However, there is a Game Breaker spell that will resurrect a dead character as an undead with half hp/mp and the same other stats, and a second post game Game Breaker that will convert an undead character to a Level 1 Human -- with the same stats. Characters that go through this are several order of magnitudes better than anything else you can field.
 * Not forgetting a spell that allows a character to be transformed into a weapon with powerful stat enhancing properties.
 * Final Fantasy Tactics by the Tactics Ogre team does something similar -- your party is limited to 5 characters max, but your available pool is 16 (24 in the PSP port). The result is that you level up 5 characters (to replace them with overpowered NPCs that join you later) and let the second stringers do the text-based missions at the bar the entire game.
 * Similarly, Orlandu joins the party with the ability to learn every single special sword attack in the game, but knowing few other skills. With a little work, Orlandu easily surpasses the other characters and stays way out ahead.
 * Particularly notable in that Orlandu not only possesses all the attacks of a previous character, AND the attacks of an enemy (Who cannot join your party), but the attacks of a character who has yet to join your party. Despite being VERY powerful, Melidoul is never used simply because Orlandu beats her to the punch and does it better, and has abilities that work on monsters (who you fight a lot of later in the game)
 * Although in the remake, Meliadoul was buffed considerately because her abilities were able to be used against monsters, which in turn meant they could be used against bosses with thousands of HP. They could also damage about as much as Orlandu's, outclassing Beowulf easily.
 * Really, Orlandu is the epitome of the One Man Party, as he's widely considered the resident Game Breaker. He's basically the I Win button. (Guess there's a reason why he's referred to as Thunder God in the story)
 * And he comes equipped with Excalibur, which grants Haste, and allows him to go first and absorb Holy damage. So when paired with the mentioned Math Skill/Holy strategy... Instant Win period.
 * In addition, a popular strategy for one of the hardest battles in the game, Wiegraf -- who the main character has to fight alone -- is to outrun the boss and buff yourself (with attack and speed increases) until you can kill him in one hit. The entire time you are buffing yourself you are getting XP, and thus after this point, the main character is 4-7 levels higher than he was before and has probably has mastered whatever job he was in at the time. And chances were, he was already the highest level party member before that.
 * This same tactic can be used in NORMAL FIGHTS, letting a character gain obscene amounts of XP and Job Abilities by setting up your secondary abilities as Squire. Ramza can do this better than a normal squire -- he has an ability that buffs several stats at once -- but anyone can do this.
 * Another related trick is to buff up Bravery to 97%. Because reactionary abilities fire off based on Bravery, a 97% bravery means you have a 97% chance of your reaction ability firing off. Several Reactionary abilities negate the enemy's attacks -- for example, a form of counter that hits first, or Blade Grasp. A 97 brave, Blade Grasping Ramza has only a 1-3% chance of ever being hit by physical attacks, meaning that until you start running into more dangerous spellcasters, Ramza is more or less invincible.
 * Any character can be made into an extremely potent One-Man Army with the Math Skill command. It is often possible to nail the entire enemy force on your first turn with a powerful Holy spell. Since Math Skill can hit enemies anywhere on the battlefield, almost every story fight can be finished before your character is put in any danger at all.
 * In Final Fantasy Tactics Advance it was entirely possible for an Assassin, due to her Game Breaker status, to become one of these without trying very hard. The Assassin has access to an attack called "Last Breath", a One-Hit KO spells. Like most spells of its kind, it is supposed to be balanced by its low accuracy. However, it is fairly easy to have an Assassin level as an Archer until it learns the Concentrate ability. Concentrate is a support ability that raises the accuracy of all abilities (Even non-archer ones) to around a 90-99% success rate. As you might be able to guess, Concentrate is nerfed into a much more moderate increase in the sequel.
 * Final Fantasy Tactics a 2 has the Viera build with the Spellblade's Blood Price ability, Red Mage's Doublecast, and Summoner's wide area of effect spells, wearing Holy-absorbing armor. With the right positioning, this lets a single character cast Maduin, one of the most practical damaging spells in the game, on multiple enemies, with no mana cost, while healing themselves, TWICE IN ONE TURN. And this is one of their many options. They can also cast any other Red Magic or Summon spell you give them, essentially making them the team healer, damage dealer, buffer, and long range attacker. The only thing they can't do is tank, but even that isn't impossible when they can cast Regen, Protect, Shell, Reflect and learn the ability Reflex, which makes them immune to normal attacks, and can equip Ribbons to protect them from Standard Status Effects.
 * This is an easy mistake to make early in the Fire Emblem games, but standard practice in the late game. Players new to the series tend to use their Crutch Character to hog all the kills, thus denying the experience points from being divided with relative equality. Due to the team-based nature of the game, weaker characters are eventually going to start getting killed off in one hit and the powerhouse, outnumbered, will suffer a Death of a Thousand Cuts. But by the end of the game, at least a third of your party will be able to waltz into the middle of a battlefield on their own and leave all enemies within range dead by the next round.
 * Some characters, like Ike, can get a little out of control later in the game.
 * Age of Wonders is a turn based strategy game in which you take over cities, build up vast armies, summon magical monsters, recruit heroes etc. It's entirely possible to beat the game using only a single unit.
 * This is a rather poor example as it can be done with 1) Any unit, and 2) Is generally more exploiting AI flaws then anything.
 * No, really. In campaign your leader (and as many heroes as you can squeeze in) appears in every mission, and retains the XP he's already amassed, so by later missions he's a powerhouse of a fourth-tier-unit level, if not stronger.
 * Shining Force plays this trope straight, with healers being maybe an exception, as they gain EXP when healing allies. Though they have pretty slow movement which can leave them too behind if you rush with all your damage dealers.
 * In Baldurs Gate 2, Sorcerers, if you start abusing some of the game's Good Bad Bugs, very quickly become this around the mid-teens. Sorcerers are considered one of the best classes for the Solo Character Run, although the most favored tends to be the thief/mage dual-class or the kensai/mage dual-class.
 * Similarly, X-COM avoids this due to the fact that even your Captains and other powerful characters are still liable to die to the first high-powered explosive to come along.
 * At least until later in UFO and Terror from the Deep, when a guy with a big gun, flying Powered Armor and game-breakingly powerful mind-control powers can take on everything, more or less. TFTD is a little harder in this respect, but you're pretty much Colonel Badass.
 * Although even the best of the best (non-cheating maximum was just a bit over 100 hps)... could be killed by few stray shots from a plasma pistol (and friendly fire... damn those squaddies!) or a single shot with plasma/sonic rifle. TFTD upped the difficulty, so even a sonic pistol can down your best-equipped, superhealthed soldiers with one shot - the chance is little, but it happens. This was due to the way damage was calculated - there was a random damage from 0% to IIRC 200% damage - 200% damage of sonic pistol is quite capable of penetrating even the heaviest armour. Not to mention alien grenades and blaster bombs/DPTs. People die in X-COM.
 * In Apocalypse, even the starting armour your soldiers have is pretty awesome. However, the final disruptor armor is nearly impenetrable and it weighs almost nothing, so you can bring a lot of weapons with you. Then there is the entropy launcher though - which pretty much eats through your equipment - whether it does or doesn't do damage to living tissue, there is a "funny" feature - as it eats through your equipment, say... grenades... funny things happen. However, add a transporter and they're back in the invulnerable territory - you can even get hit by a missile launcher and teleport away before the damage actually gets to you. A popular tactic in the endgame is to transport in, drop your bombs and transport right out with a second transporter. There is no stopping you in realtime mode :) (except for psi, damn)
 * Arc the Lad has a 50-level dungeon in the first game where you have to traverse all 50 levels in both directions, without any save points or exits in-between. It is quite possible to have only a single character survive this process, and this character may become considerably more powerful than the others as a result. With the second and third game allowing you to bring in characters from the previous games at certain points, this character may continue being a dominant force for some time. The character in question is usually Tosh, the swordsman, becoming the sole survivor around the 20th level on the way down... meaning he fights 80 difficult levels entirely on his own. Thanks to his time out before getting re-recruited in the later games, the rest of the party is finally able to catch up late in the third game....
 * Arc 2 has optional character Choko, a walking, talking game breaker who's a force to be reckoned with even at level 1! Level her enough and its no exageration that you'll probably never have to attack with anyone else for the rest of the game. And thats even before the optional sidequest that unlocks her ultimate attacks. Equip her with the infinite MP accessory, and she's invincible. Though the final boss is so damn hard that using her is almost a requirement.
 * In a SPRG that's relatively unknown to the English-speaking masses called Sangokushi Sousouden, which is based on the Three Kingdoms period and has Cao Cao as its protagonist, the enemies' level are based around the average level of everyone who you have sent out in that battle (and there can be up to 15 participants in bigger fights). Can you imagine what it would be like if you send out Cao Cao at max level (50) and everyone else at a very low level (like 3-5 or so)?

Sports

 * Tsubasa Ozora happens to be a lot stronger than the rest of the Nankatsu, Japan, and whatever teams by stats in most of the RPG-like adaption of Captain Tsubasa game, and tends to gain levels a lot faster as well. With his stock special skills, He's easily outwitting other aces aside from Hyuga and be a Game Breaker, just like how he is in the anime/manga.