Responses
'Ajin'-- the mc is a kid but there are also grown ups fighting, the manga is a solid 10/10 tho def give it a go.
'Alive, the final evolution'-- read it a long back so don't remember much but the mc is a kid, and i believe it was a good read.
'Shotgun boy'-- also read other series from this author cause they're all pretty good, this ones kinda vaguely supernatural I'd say
Blue exorcist
And maybe you'd also like danganronpa?
Dead Account
A comic similar to MHA/Assassination Classroom? High school bg with the kids having superpowers/plot, but an actual kid not a man/woman in their 20s going back in time. I've read the f, iruma, and world destroyer smth. They mad fun to read