Hello

Ok, so I read this fic a while ago and thought, "Huh, that's an interesting headcanon!"

Then I reread the manga.

This isn't just a headcanon for me, I am full on CONVINCED that Hayashida intended this to be the case and just never confirmed it. She doesn't seem to be one for coincidences in her writing and there's a little TOO much evidence to ignore.

What theory, you ask? Well, let me just give you the evidence and you can see for yourself...

(drhdr spoilers ahead)

first of all, we don't really know anything about Ai's family besides his grandpa, and he's not necessarily confirmed to be biologically related to Ai. He could have very well been adopted.

Ai looks very similar to someone else in the manga

"ah, but Ai and Haru don't have any connection other than Kasu-" WRONG

Kai's lab was in Haru's house! and there's this scene

Okay, so singing at random times isn't necessarily out of character for Haru, but what are the chances she starts singing right when Kai's being attacked by Curse? (for those who forgot, Devil song drives off curses)

of course, we all know Ai is academically inclined like Prof. Kasukabe, and they had something of a familial bond. (also in the anime, Kaiman/Aikawa's skin tone is closer to Kasukabe's than any other character. It's not as dark, sure, but the similarity is there.)

also Haze/Kasukabe is 64, Haru's 59, and Ai/Aikawa/Kai/Kaiman is 28, so the ages line up

The real kicker is these scenes…

He's your what, Haru? Spill

I'm sure you're pretty convinced by now, BUT THERES MORE

now, this is my writer brain turning on, but there's a specific motif that my boy Kaiman (and Kai) is drawn with throughout the manga

you know the one

obviously this is a reference to a hydra and Kaiman's multiple heads

EXECPT there are two other characters that have a snake motif!

Kasukabe

and haru

none of the other characters in Dorohedoro are ever drawn with a snake theme. The only other character that’s ever drawn with a snake at all is Nikiado, exactly once, which is probably a reference to her partnership with Kaiman.

now, there’s definitely some things that need clarification. First of all, why is Ai human? Well, the idea that Ai was born a half sorcerer actually holds water. After all, Kaiman’s devil tumor was destroyed. It wasn’t confirmed whether the rest of his body returned to being human or not, which leads me to believe that he’s still physically a sorcerer except for the fact that he doesn’t have a devil tumor. Remember, a devil tumor is supposed to represent a sorcerer’s life or soul, but humans don’t have or need a devil tumor. So, theoretically, wouldn’t it make sense that someone who’s half human/half sorcerer could survive having their devil tumor destroyed? Something a full sorcerer could never do?

He may have been turned human by a devil then the former devils reversed that spell. Why was he turned human, and by who? Well, I have some ideas, but I won’t go into that now. You can come up with your own interpretation ;)

Basically, I think you can draw your own conclusions at this point

Average day in Aikawa's life: