#also i think its worth noting how sigma seems to be a 'cooler' version of our weretiger in some ways

[note-boom]

Ik this is random and is gonna sound crazy but i had this theory that both sigma and atsushi were created by the book since both. Have black n white hair,some sort of white color scheme(albinism?) And seem to be both REALLY socially akward as if they DIDNT spend enough time around humans(in sigmas case ofc but atsushi? He grew up SUROUNDED by other kids,and ofc he was an outcast and he was probs afraid of punishment so ofc that could be an explanation) both are REALLY similar

They aaaare, and it's not crazy (have you seen canon?)!! I've seen stuff about Atsushi and Sigma parallels and it FASCINATES me how similar they are (I read the Sky Casino arc and MAN was that intense).

And while I don't know enough to disagree or agree with your theory OP, canon HAS already stated through Fitzgerald that Atsushi has a connection to the book. And considering how Sigma was created from the book and how you and the fandom in general see to see Sigma and Atsushi as incredibly similar....well, there's definitely SOMETHING going on in there.

(Also, there's another post I know that also pointed out how Q was similar to Sigma design-wise, which I was reminded of with your ask....I don't know if there's a point to that but...)

I do think so far, though, that Atsushi is human. He's mentioned to have parents and his childhood seems to be pretty well established. Of course this is a seinen action manga and they always seem to have the most convoluted plotlines. Like just watch as they pull out a plot twist that Atsu and all his backstory WAS created by the book and that the beginning of the manga is the beginning of his true birth...please don't take that seriously...

Anyway, I went on an unrelated tangent again (as usual) but thank you for the ask, OP!! I don't think about Sigma/Atsu parallels enough and your theory definitely isn't crazy...but we shall have to see.