Sgt. Frog/WMG

Keronians' sex organs are on their heads.
In one episode Giroro is grossed out by the mere suggestion of Keroro taking his hat off. They don't wear any other clothes, why would they only wear hats and consider it taboo to take them off?
 * ... naw, too easy.

Koyuki is an orphan and not a ninja.
We don't see her parents, and despite living in a "secluded village", we never see other ninjas. Koyuki actually seems to live on her own, since she has no problems with Dororo making unannounced appearances, and she became obsessed with ninja as a coping mechanism for the apparent absence of a family. Dororo is likewise interested in her hobby, but particularly understands the feeling of being left out and forgotten.
 * Jossed; in both the manga and anime, we see a flashback to how Koyuki met Dororo, and it shows the members of her ninja village being told to disperse and integrate with modern Japanese society. Of course, we still don't see Koyuki's parents, so she might be both an orphan and a ninja. Though we may not see Koyuki's parents BECAUSE they are ninjas.

Tamama's growth is stunted by high blood sugar and his jealousy.
Thinking about it, it makes sense that the two would be related. There are people have had their growth stunted by drugs, alcohol and even being angry all the time so it's possible that Tamama's candy addiction is the reason why he hasn't fully matured yet. To prove my point, if you look at the crowd that Tamama is standing with during the Kero Zero short you'll notice 1-that a lot of his supposed age mates look older than him and 2-that he's just as addicted to candy on Keron as he is on Earth.
 * Jossed, his growth is actually stunted by his powers. Namely his Tamama Impact.

Fuyuki and the Keroro platoon may be a Reconstuction of Dib, Zim and Gir from Invader Zim, with the other cast as other characters
If this holds true, then:
 * Fuyuki is the Keroroverse version of Dib, albeit a well-liked non-crazy version.
 * Keroro is a heavily diluted form of Zim, ocassionaly featuring his rage and lust to conquer earth, but usually just being lazy and stupid.
 * Giroro is a personification of Zim's drive and reckless determination to conquer earth, though not nearly as insane or stupid as Zim.
 * Tamama represent's Gir's "Duty Mode" cranked up to 100.
 * Kururu is Zim's ocassional technological aptitude.
 * Dororo is... I give up. Someone just wanted to throw a ninja in for good measure.
 * It does add Instant Awesome.
 * And Natsumi is Gaz. Also, Momoka is Gretchen and Pururu is Tak...this fits much better than I thought.
 * Slight problem - Keroro Gunso(1999-present) is two years older than Invader Zim(2001-2002). Alternate theory: Jhonen Vasquez was Separated At Birth from Mine Yoshizaki. Magic Plastic Surgery was involved. As were Human Popsicles. Along with ridiculous amounts of whatever the Japanese put in their candy. Turn of the millennium, they both decided to make weird series about Ineffectual Sympathetic Alien Invaders. Eagle Land, being so lame they're lame, killed Invader Zim after two seasons, despite its fanbase. Japan, which prides itself on being geek Mecca, has made seven seasons of this madness, along with twenty volumes of manga - there are entire shelves of Keroro swag, just like in the opening sequence of the first series!

Keroro is a faulty clone of the original Keroro.
The Keroro we know and love from the manga/anime is actually a clone. Either the original Keroro met an unfortunate accident, or 'Keroro' was meant to replace his famous, revered father. But something went awry with the process, and Keron Force dispatched him to Earth without realizing that he was flawed.
 * This means that

Keroro and company arn't products of Shinji hillucinating, rather it's the OTHER WAY AROUND!

 * Though I can't belive that nobody has suggested that their products of instrumentality yet. Anyway, my theory is that Keroro witnessed Neon Genesis Evangelion during a bad trip in his Lotus Eater Machine, the "Space Dreaming Plant Alpha". He then told Aki about the dream, and she made it into an anime.
 * Just more proof that it was bad for his health.

Obligatory Evangelion Theory
You know the drill: Shinji hillucinated the whole thing, blah blah blah, intrumentality.
 * Shinji = The nieve Fyuki
 * Asuka = The hot-headed Natsumi
 * Rei = Momoka, who Fyuki is shipped with seriously creeped out by.
 * Misato = Aki, attractive motherly figure.
 * In the manga, when Fuyuki and Natsumi first mention their mother, Keroro's image of her is strikingly similar to unit 01.
 * The Keroro Platoon = A really, really, REALLY messed characature of the Angels.
 * 623 is Kaworu.
 * Actually he is, judging from episode... 10 was it?
 * Episode 9, Kururu's official introduction.

Starfruits originated from Keron and have become extinct there.
They were brought over by an invasion force prior to the Sergeant's and eventually adopted by Pekoponians. Back on Keron, a parasite wiped them out. This explains why (as Kururu noted) it was "strangely high in Keronian planet essence". There are no records of starfruit left on Keron because they have been rendered extinct for a long time, and it's high in Keronian planet essence because it's from Keron.

Giroro's cat is secretly an alien invader.
She's trying to soften up the platoon (or at least Giroro) in order to divert their attention from their invasion of Earth so as to allow her comrades to take Earth without trouble from them.

Joriri is Keroro's real father.
Come on, they're both rather dim and silly, and green, and they have the same eyes. Joriri is far more like Keroro than the Demon Sergeant. Not to mention they've always been close, to the point were Joriri now lives somewhere in the Keroro Platoon's base. A father secretly looking after his child? Hmmm...
 * Alternatively, he could be Keroro's lazy uncle. We do see that Keroro looks a lot more like his mother than his father.

Keroro's friendship with Fuyuki is partly a 'do-over' for his friendship with Zeroro.
Several parallels can be drawn between Fuyuki and Zeroro. Both are (or were) soft-spoken young men with Shrinking Violet tendencies. Both have few friends at school, and are delighted to have Keroro for a best friend, despite all the trouble that friendship leads them into. Keroro, naturally, takes full advantage of that. Both are slow to anger, but terrifying when they finally snap.

As dense as Keroro can get, he has picked up on the similarities, even if only subconsciously. He also got to see how Zeroro turned out, and has been shown to regret it (even gaining a 'Guilt Switch' in the anime). But this time around, he can do it right.

...Not that he's actually all that good at maintaining that resolve. But Fuyuki does sometimes function as a sort of Morality Pet for him at times, and he does appear to put more effort into actually acting as his friend instead of just using their friendship for his own ends.

The Keroro Platoon was never expected to actually invade because, unknown to them, they're just there to make a profit-grossing TV show for a company on Keron.
While the Keroro Platoon is fully aware that their antics are being aired on Keron television, they still think it's an 'update on the invasion' sort of show and is completely serious. But, what if they were never actually expected to be competent enough to invade in the first place? Think about the platoon. You have a lazy Man Child for a leader, an obsessive and insane-but-cute bi-polar foot soldier, a gun crazy, super serious Corporal, a perverted and cruel tech specialist, and an emotionally disturbed ninja. Who would seriously let these people in the military, let alone on a famous invasion, to be viewed as intergalactic poster boys of the Keronian race? People who want to make money.

But, who are the real ones working here? The Garuru Platoon. They were hired by the TV company to patrol around Pekopon so nothing actually deadly could come and kill their Cash Cow Franchise. Every Monster of the Week that finds its way into Tokyo was actually planned and purposely let loose on the Keroro Platoon. Most of the enemies, like the Shurara Corps, are actually just actors. Pretty much, everything is a lie, created to make some Keronian CEO very rich.


 * This means that the Garuru Platoon's appearance to replace the Keroro Platoon was simply a Ratings Stunt, a Cliff Hanger to keep the viewers watching.

Private Tamama is secretly a cannibal.
How else would he know that Giroro tastes like octopus ball? Clearly, he secretly nibbles away at the platoon when they don't know it.
 * Well, he did drink Giroro when he became a liquid.
 * But then he threw him up becase he tasted gross and that whole incident was caused by Tamama mistaking Giroro for strawberry soda, perhaps what happened was that Giroro touched something and Tamama put it in his mouth and it tasted more octopus-ish than usual. Saying that the Animax dub of episode 169 might have Tamama say that liquid Giroro tastes like octopus ink
 * Alternately, his knowledge of how Giroro tastes may be related to his sexuality. Oi vei!

Fuyuki and Natsumi's dad ran off with Dib and Gaz's mom.
Mr. Hinata was a prominent scientist in Japan. He went to a conference in America one year at which he met Dib and Gaz's mom, who had an impressive career of her own at the time but was unhappy in her marriage to Professor Membrane. The two fell madly in love and ran off together, explaining their absence from both canons.

Anime!Pururu's Heart Symbol raises her Charisma to Mary Sue-levels.
In Volume 15 of the manga, it's revealed that the Keron Star boosts the wearer's Charisma dramatically. Keroro's abrasive personality lowers its effect to roughly 'balance out'; when he loses it in one chapter, none of his friends can bring themselves to care. And when the Star ends up on somebody else who's already naturally charming, they immediately make them the leader and follow every command without question. Even Kururu is drastically affected.

Compare this to Pururu. While the Manga!Pururu is not treated as insanely charming (coming off as more of a Yandere who captures Natsumi's heart by telling her to torture Keroro more), in the anime, she's basically a Canon Sue: everybody loves her, falling all over themselves to impress her, and despite being assigned to a different platoon (the elite Garuru Platoon, natch), she's treated more like a Sixth Ranger. Clearly there's something going on there, and since the manga has already confirmed that the Keron Star has a special effect on its wearer, and the anime is quite fond of Flanderization, they just tweaked that idea to suit their own needs: metaphorically pimping out their chosen Canon Sue.

The whole invasion is actually not for the sake of conquest.

 * First off, the Keronian military is way too powerful for them not to be currently engaged in an all out war. Thus, they are at war.
 * Second, Viper, Viper the elder and so on and so forth are shown to be, despite remarkably bad tactical sense, a match for anything but a full platoon of Keronian military troops. If their entire race follows that path then by simple mathematics, the Keronians are fully engaged against Viper forces.
 * Viper and his race are, to be straightforward, snakes. And aggressive, cruel and sadistic. And not exactly against using humans as bait for the platoon.
 * The Keronians, despite their heavy military theme, and WW 1 Axis powers theme, have plenty of allies, including a race who could be considered virtually gods, as they can destroy entire planets. Additionally, the fact that 566 'opposes' Keroro and his platoon can simply be taken as a sign of his insanity, rather than any true heroism. And the fact the actual 'space police' aren't opposed to the Keronian's, when presumably they work for an equivalent to the Space UN, which should oppose illegitimate wars of conquest.
 * Both the Keronian military and Viper have shown they have technology centuries in advance of Earth's best available assets, including bio-engineered supersoldiers (Tamama). As such, our own military would be easily overwhelmed (as the introduction suggests we would have been).
 * Despite the fact he's supposedly a ruthless military invader, Keroro and company have actively gone out of their way to befriend people, so even the most jaded and misanthropic of them has become close to someone. Indeed, when offered a chance to actually conquer the world by ruthless means, Keroro balks at the idea.
 * As such, from all this, we can conclude that the Keronian military plans to use Earth as a stepping stone on their next strike into Viper controlled territory. This would most probably be a flanking manoeuvre.
 * Another possibility is that they're here as scouts or guards- an early warning system to see if the enemy shows up in any real numbers in this part of the galaxy. The "conquering" thing is a silly pretense to avoid freaking out their hosts and causing mass suspicion and panic.

The Angol race prophesized to destroy the Earth are, in fact, benevolent beings, intending to save the rest of the galaxy from human expansion.
The introduction of Angol Mois's cousin in Soul Calibur 4 suggests that this was the purpose of their mission, but that their actual observations upon arriving find that there are many sympathetic humans who didn't do anything to deserve death. It also explains why Angol Mois, along with her family the few times you see them, are extremely friendly.

Sergeant Major Kururu is the embodiment of the Yellow Peril.
Many Japanese (and Westerners) used to believe the stereotype of the Chinese as a sly, tricky, sneaky people often with coke-bottle glasses, exaggerated teeth and yellow skin. The fact that Kururu fits ALL the stereotypical aspects depicted in the Yellow Peril view of the Chinese makes him Unfortunate Implications incarnate.
 * This can also explain why he is by far the least popular character merchandise-wise.
 * I always figured it was the opposite. The way he calously experiments on live humans coupled with the Imperial Japan theme the Kerons have makes him seem like a (nominally) kid-friendly version of Unit 731.
 * That's because of how the Yellow Peril evolved. The trope was originally Chinese, but gradually came to symbolize all Asians, and was definitely played up in allied propaganda depictions of the Japanese during World War II. It wouldn't be too far of a stretch that Mine Yoshizaki drew him with that in mind, considering the Keronians are already a satire of World War II Japan.

Zoruru's grudge against Dororo is pure jealousy.
In Volume 17, a Flash Back reveals how Zeroro and Keroro met: Zeroro was a Shrinking Violet New Transfer Student, and Keroro called him over to play. Innocent enough... except Zoruru was standing right behind Zeroro at the time, and was completely ignored. The flashback doesn't go into any further detail about his motives, but that's what this is for. It's framed to look like Zoruru wanted to get Zeroro's attention, but here's the thing: we don't know how long he was attending that school. So what if he'd always wanted Keroro's attention -- or even just for someone to notice him? Yet nobody ever did... and then here comes this shy new transfer student who, without doing anything, immediately makes a brand new friend. Effortlessly -- or at least, that's how it looks to him.

In other words, it was never about Zeroro at all. Zeroro's just a hapless Scapegoat. (The fact that Zeroro's recognized as the best assassin, yet is completely exempt from the usual assassin's fate of fading into obscurity doesn't help much either.) That's why their latest fight ended the way it did: Keroro finally noticed him, and the result... wasn't exactly what Zoruru expected.

Zeroro never actually assassinated anyone.
Volume 17 includes a Flash Back where Zeroro's mentor compliments him on earning top marks in all of his exams... then goes on to say that because he's rated as the top assassin, he can't actually become the master assassin. He explains over Zeroro's protests that it's the assassin's fate to be forgotten, then goes on to point out his kindness, stating he'll serve better as "an ordinary soldier". When Zeroro continues to object, he adds "The darkness of the assassin's path is deeper than you can ever imagine."

So Zeroro was an assassin In Name Only, probably with little to no field experience prior to joining the Keroro Platoon. He may serve more as a public 'face' for the program, to allay concerns about the military having an assassination branch. This also feeds into the above theory, if Zoruru is aware of his rival's inexperience.

The anime is actually the Cash Cow Franchise produced by Keron Force.
In keeping with the earlier WMG about Keron Force actually sending the Keroro Platoon to Pekopon just to spawn a popular TV series, the anime actually is that series. That explains the massive Flanderization, Adaptation Decay and Filler compared to the manga; the manga is a more accurate portayal of events (not available on Keron), while the anime is the result of their efforts and massive Executive Meddling.
 * Dororo was built into The Woobie-slash-The Chew Toy to try and offset the fact that everyone has trouble remembering him. After all, they can't sell toys of a character nobody recognizes, right? (Plus, they don't want to glorify the Pekoponian Ninja Arts too much, which is why he's significantly weaker in the anime and easily neutralized by his Trauma Switch.)
 * Originally, they planned on replacing the unpopular Kururu with Hospital Hottie Pururu. That didn't work out, so they've resorted to having her show up as often as possible, turning her into their Canon Sue.
 * They refuse to acknowledge Character Development because they assume Viewers are Morons. This is also why they rely so heavily on the Fleeting Demographic Rule, such as repeating the "Momoka tries to set up a romantic interlude with Fuyuki" plot over and over and over...
 * The anime-exclusive characters were added to try and boost ratings. For instance, Joriri was inserted because the execs feared they weren't getting enough 'silly Keroro antics' in their Whole Episode Flashbacks (which are constructed from whole cloth anyway...), so they whipped up an Expy and called it a day.


 * In one of the manga chapters we learn that the Platoon's antics have been turned into a show called "Tales Of The Keroro Platoon" which is broadcasting on Keron. This means that the anime is a Show Within a Show of the manga. And later in Volume 17, we learn that it is celebrating its 5th anniversary and (according to Tamama) they tell a lot of lies.

In the manga, Sumomo's manga adventures have made her a celebrity on Keron.
This is why after the Keron robot gets whacked by Mois, its head opens to reveal a plushie of her. She's become a celebrity (albeit for different reasons from the anime).

Keron is ruled by the Ogdru Jahad.
Violent, expansionist frog people who use Humongous Mecha? Certainly sounds like their doing.

Each member of the Keroro Platoon represents a different period in Japanese history.

 * Dororo: Feudal Japan. There's the obvious ninja thing, plus he's exrememly sensitive to shame & often reacts violently to it.
 * Giroro: Post-Tokugawa-era. Gentlemanly; strong, if somewhat outdated warrior code; has trouble interacting with different cultures he's just met, but he's learning.
 * Kururu: WWII-era. A smug, sinister, casually cruel little freak who has no problem performing experiments on live, human subjects.
 * Keroro: Late 20th Century, especially post-fanancial crisis. Basically decent, but spends way too much time obsessing over nostalgic Humongous Mecha shows . Perpetually broke & seen as a bit of a joke by his contemporaries.
 * Tamama: Modern Japan. Comes off as very cutesy, but hides (poorly) serious mental problems just below the surface.

The members of the Keroro Platoon represent the Seven Deadly Sins.
It requires a bit of doubling up, due to their only being five of them, but still:
 * Keroro: Sloth (never does his job/chores), Avarice (for Gundam Models)
 * Giroro: Wrath (should be obvious)
 * Tamama: Lust (for Keroro), Gluttony (eating candy all the time)
 * Kululu: Pride (he thinks he's awesome, and doesn't hesitate to treat everyone else like dirt)
 * Dororo: Envy (envious of anyone with friends)
 * I think lust is more split between Giroro and Kururu with Tamama having envy
 * Dororo doesn't have envy at all. Not even a slight bit of jealousy. Dororo is more of a guy who presents all of the Seven Heavenly Virtues. Tamama is the EMBODIMENT of Envy which goes way further than his lust.

Shurara's helmet was created using a combination of technology found in the Reality Pen and the Kirurus.
Shurara's helmet was a banned weapon on Keron, seeing as it was found too dangerous. It was created so the wearer could use their mind to create all that was needed for a successful take over. A Kiruru-mechanism was placed in it as well that could be manually activated to finish the job. Things did not go as planned, however. Due the the amount of that element that makes the Reality Pen work (Imagine most of the helmet being made of it or an alloy with it in it), the helmet could take on it's own form of sentience, using the user's mind and amplifying the negativity (thanks to the Kiruru parts). The user would eventually loose control and the helmet would activate the take-over switch on its own. It was banned, buried where no one would find it... Until a certain tadpole happened upon it...

Kururu is Dangerously Genre Savvy about Shipping.
He's aware that he's the least popular member of the platoon, and has shown occasional signs of being dissatisfied with that... in his own creepy way. His constant flirting and harassment of Giroro in the anime is a bid to become more popular by intentionally invoking Ho Yay. He knows about Kichiku Megane and is playing that to his advantage.

Another Invader Zim Parallel: Keroro was exiled to Earth
The Keron military is embarrassed by Keroro and his antics. Rather than giving him a dishonorable discharge, the higher ups (possibly influenced by any of Keroro, Giroro, or Dororo's fathers) decided to dispatch him to Pekopon so he can muck around all he wants without causing trouble. The rest of the platoon is there to make sure Keroro doesn't do anything incredibly stupid or seriously hurt himself, and they're mostly putting up a show for him. Perhaps even the Hinata family is in on it too. The Garuru platoon's "mission" was either a training exercise or to see if Keroro has learned his lesson.

As a parallel to Invader Zim's theory of the same type: All this is happening in Real Life.
The Keroro Platoon will eventually confront Zim and the two sides will fight. Victor gets dibs on the planet.

Funny Afro Dasonu Maso's song can be defeated too with the Rick Roll or Caramelldansen.
In any case, any ugly song by any Dogmatic Space Aliens are just cannon fodder for the awesomeness of the Rick Roll.

Natsumi and Fuyuki's Dad died after watching the cursed video
Perhaps its like this. Little Fuyuki was just developing an interest in the occult, and someone gave him a copy of the cursed video. He watches it, but does not understand the consequences. Natsumi doesn't believe the "stupid legend" so he shows it to his father (Who for the sake of keeping the seasons pattern up will be most likely named Haruka or something similar) Fuyuki unwittingly cursed his father to die from the curse. However, when the time's up, Mr. Hinata is at work, and suffers a fatal heart attack. Everyone thinks he overworked himself to death, but only Fuyuki connects it with the curse. As a result, his love for the occult intensifies.
 * Jossed, Haru Hinata comes home at the end of ep 357. We do not see his face, but we see in an old picture that he has Natsumi's pink/red hair.

There is an Ancient Conspiracy related to the keronians
Along the series there are little hints that keronians have been on earth before the invasion failure, but everytime it appears, it is let unexplained, sometimes rising even more questions.
 * Clues to past invasion attempts include: the ancient Kirurus, the secret Keron base in Machu Pichu where Dark Keroro was born in, the "kappa" that the Hinata ghost had befriended in her time, and the ancient planet compressor hidden underground in episode 27.

Keronians have Funny Afros under their hats.
Their battle afros that they wear over their hats are a sort of decorative and functional codpiece. This is how Keroro can have a Funny Afro from being caught in an explosion without having had enough warning to put on his battle afro.

Zeroro/Dororo is blind, and "sees" using some sort of ninja skill.
This is why he has blue pupils and a complete inability to color inside the lines (such as the time when he and Tamama tried to help Aki finish a chapter of General Frog before the deadline). He treasured his music box because it's a sound-based gift that he received when he was young.

In the anime, Tamama hates Mois not because of jealousy, but because of an unrequited obsession with her.
In the beginning back when Mois was first introduced, Tamama did feel jealous felling towards her for being close to Keroro. However, as the series went on, it is made somewhat clear that this "jealousy" made him focus more on "that woman" than Keroro. Somewhere along the way, at least in the subconscious level, he hated Mois not because Keroro pays so much attention to her, but the other way around. Tamama remained believing in the former either because of ignorance or denial.

Mois was rather lonely as a kid.
Being a member of the planet destroying Angol tribe, she probably did not have a lot of alien beings to play with due to their fear of the tribe. Keronians, being friends of the Angols, were an exception. This could explain how Mois and Keroro first met and why Mois fell in love with him in the first place.

Mois did not see Keroro again for about two thousand years, or at least what felt that long.
According to the manga, Mois is 2000 Earth years of age, yet somehow met Keroro as a child. Normally, this sort of thing would not make sense. But, as confirmed by Fuyuki in the anime in episode 283, time works differently in different regions of outer space. Therefore, Angolans, at least in their sector of outer space, probably mature faster than other species.

Keroro and Giroro were close friends as kids. However, at one point in time they fought and separated over a major issue. They then became Fire-Forged Friends during the Keron War.
It would explain why Keroro cut Giroro deep enough to give him a permanent scar and also why they appear to have a closer/different relationship than any of the other platoon members.

Koneko, Giroro's cat, is Kotomine's nameless wife.
As we see her in Fate Zero, she's a White-Haired Pretty Girl with Eyes of Gold, which matches both Koneko's real body and her human form. Her fondness for Giroro is partially because he was kind to her, and partially because his voice is one that's beloved to her. Tragic, if you think about it: Either it's reincarnation, where Kotomine/Giroro is capable of love, but not for her, or it's a prior incarnation, and Kotomine's wife was convinced that he did have human feelings because she remembered their Keroro Gunsou incarnations... where, ironically, Kotomine/Giroro wasn't even human.