9 Shonen Anime Theories So Good You’ll Want To Adopt Them As Canon

Kite's Weapon Choices Aren't As Random As They Appear

While there are endless ridiculous fan theories that come from shonen fans across the world, every once in a while you hear one so smart you basically adopt it as canon.

For this list, we’ll be looking at some of the coolest shonen anime fan theories specifically about heroes. They touch on topics like Katsuki Bakugo’s anger problems in My Hero Academia, Yuji Itadori’s true lineage in Jujutsu Kaisen, the possibility of Nami being the human manifestation of an ancient weapon in One Piece, and more.

These theories are part of a crowdranked list from Ranker, with over 900 voters contributing to the ranking. We’re presenting them as a countdown, with the #1 voted-on theory last.

9. Goten Was Conceived While Goku Was In Super Saiyan Mode

Goten Was Conceived While Goku Was In Super Saiyan Mode

Why is Goten able to go Super Saiyan so quickly? Most characters are able to transform only after intense training, but for Goten, it came after only very light training under his mother. Redditor u/Logic_Nuke has an idea about what happened. 

The time period when Goten was most likely conceived is during the nine days prior to the Cell Games. During this time, Goku was constantly in Super Saiyan mode for training purposes. This means that he was most likely conceived while Goku was transformed, which might give him easier access to the form himself. 

Toriyama says that Goten can do this because he inherited a ton of S-Cells, but it’s entirely possible that he inherited those because of Goku’s transformation.

8. Norman Is Left-Handed & The Symbolism Matters

Norman Is Left-Handed & The Symbolism Matters

Norman isn’t clearly left-handed – in fact, he seems ambidextrous, since he’s seen using both hands under different circumstances. Redditor u/SymphonyofPromises noticed that there’s a huge difference between the times that he uses his left hand versus the times he uses his right hand.

The difference is that when he uses his right hand, he’s doing things that don’t reflect his true desires, but Minerva’s. He’s doing what he feels he has to do. When he uses his left hand, he’s doing what he actually believes is right, and wants to do. Whatever he does with his left hand reflects his true self – which means that he’s left-handed. 

Does the symbolism in The Promised Neverland really go that far? Hard to say, but the idea is fascinating.

7. Yukina & Hiei Have Yet To Hit Puberty

Yukina & Hiei Have Yet To Hit Puberty

No one is quite sure how old Yukina and Hiei are. Yukina is an ice demon from a race that gives birth to a baby girl at age 100, and then continues to do so for the rest of her life. The same applies to Hiei, her twin brother, although his reproductive abilities have yet to be explained. Yukina hasn’t had a child yet, so she has to be less than 100 – but how much less? No one knows. 

Solid Script doesn’t know exactly how old they are chronologically, but they’re pretty sure that developmentally speaking, they haven’t hit puberty yet. That’s because Yukina is a literal clone of her mother Hina, which means that if she were an older teenager she’d look a lot more like her mother. This person places them at a developmental age of 12-14, which puts them in line with the rest of the cast.

That said, they’ll be aging much more slowly, which puts a damper on the future of Kuwabara’s crush on Yukina. 

6. Why Do Naruto’s Kids Have Whiskers?

Why Do Naruto's Kids Have Whiskers?

Naruto’s kids were born with whiskers on their faces, a trait that they inherited from their father. But Naruto got those whiskers because he was exposed to Kurama’s chakra while still inside of his mother, a jichuuriki. Presumably, Hinata gave birth to Boruto and Himawari, so where did the whiskers come from?

Fans have a lot of ideas about how this could have happened. Some think that Naruto passed some of Kurama’s chakra on to his children, which he was able to do because that chakra altered his genetics. Does that mean that they’ll ever be able to manifest any of Kurama’s powers? Some fans say yes, others say no.

5. Kakashi’s Ninken Are Therapy Dogs

Kakashi's Ninken Are Therapy Dogs

Kakashi makes liberal use of Ninken, or ninja dogs, in both his battles and his everyday life. This has led some people to believe that Kakashi might actually be related to the Inuzuka clan – but it’s possible that he has another reason – they double as therapy dogs.

From his father’s suicide to his life as a child soldier and his teammate’s violent demise, Kakashi has been to hell and back. It’s extremely unlikely that he isn’t suffering from PTSD or some other mental health issue. Dogs can be enormously helpful for helping a person cope with symptoms stemming from those things. It’s possible that Kakashi’s Ninken are also helping him deal with his painful past. 

4. Yuji Itadori Is A Descendent Of Sukuna

Yuji Itadori Is A Descendent Of Sukuna

Why was Yuji Itadori able to handle housing Sukuna in his body? This is supposed to be nearly impossible, so much so that most of the sorcerers would rather see him destroyed than let him try. One theory, proposed by Redditor u/religiousn, is that he might be biologically related to Sukuna.

We know very little about Yuji’s familial background, but his parents’ true identity is heavily hinted at. So, we know his lineage is important. We also know that the two of them look a lot alike. While this could a be Yu-Gi-Oh!-esque visual convenience, it’s also possible that it’s because he’s a descendent of the Ryōmen clan that Sukuna hails from.

3. Kite’s Weapon Choices Aren’t As Random As They Appear

Kite's Weapon Choices Aren't As Random As They Appear

Kite’s Nen technique, Crazy Slots, lets him summon a sentient clown with a roulette on its tongue that lands on the numbers 1-9, and get a different weapon depending on the number. His inability to choose the weapon is a trade-off for increased power.

Redditor u/fhernaiz thinks that there’s a good chance that the choice isn’t entirely random. On more than one occasion, Kite criticizes the clown for giving him a ‘bad roll’ which the clown objects to. Ging also claims that Kite has a number he rolls when he’s in a really desperate situation.

This likely means that while Kite himself doesn’t get to choose his weapon, the clown does – and the clown chooses the best one for the situation. 

2. Madame Christmas Adopted Roy Mustang 

Madame Christmas Adopted Roy Mustang 

Roy Mustang was raised by his aunt, Madame Christmas. She’s a brothel and bar owner who also works as an intelligence operative.

RinKat posted a theory to Amino Apps that states that Madame Christmas isn’t biologically related to Roy. Instead, his parents were either fellow intelligence operative or criminals with a connection to her who ended up passing away tragically and leaving their son to be raised by a woman who pretended to be his aunt. Either that, or she simply found an abandoned child, and didn’t know who his parents were. 

This theory works in concert with the popular idea that Roy is actually Xingese. His biological parents, in this scenario, are originally from Xing. 

1. Bakugo’s Anger Is Caused By His Quirk

Bakugo's Anger Is Caused By His Quirk

Why is Bakugo so angry all the time? It could be his inborn personality, it could be his mother’s abusive child-rearing methods, or it could be that thing his mom said about him having a superiority complex that’s fed by constant praise. But this fan theory posits that the real reason might have something to do with his quirk. 

Bakugo’s quirk works by secreting nitroglycerin-like sweat from his palms. Nitroglycerin can dramatically lower a person’s heart rate. In order to achieve homeostasis, his body could be producing huge amounts of adrenaline. This keeps him alive, but it also keeps him constantly stressed out and angry. That can’t be good for him long term!