CHARACTERS I HEADCANNON HAVING AUTISM AS A PERSON WITH DIAGNOSED AUTISM
Izuku Midoriya from My Hero Academia
He also has ADHD though both are on the mild/moderate side of things and he has been diagnosed. His special interest is Heros especially All Might.
I'd say moderate/severe side of things and probably diagnosed since his parent is Orochimaru. His special interests include random facts about all of the hidden villages , especially Konoha , and the Uzumaki family.
Kaeya Alberich from Genshin Impact
Don't know what what level he's on , but he's definitely undiagnosed. The playing he does with his sword in his idle animation is him stimming. He masks. A lot.
His special interest is pokemon obviously. He also has ADHD and both are undiagnosed.
Remus Lupin from Harry Potter
I made a headcannons page for him before that lists some of this already. He is diagnosed
Keigo Takami aka Hawks from My Hero Academia
He is on the moderate leaning towards severe side of things. This special interest is plains
Diluc Ragnvindr from Genshin Impact
His isn't as bad as Kaeya's and once again is undiagnosed. His special interest is birds