powers from demon slayer is hamon. i haven't read demon slayer but from what i've seen and heard the protag isn't OP it just happened that his ability was a perfect counter for the main villain. but then again jonathan is basic vanilla powers. so things could go either way.
better go with jack if you want a good boss killer or achilles for utility he can practically do it all , good crit damage for boss fights , NP gain is ok too and his quick buff from his NP is nice too.
tamamo kinda sucks , she's the weakest imo even back then when there were only 3 big supports.
have you guys seen this game? i'm really digging the aesthetics and thme.
edit: so i tried it , and it looks good , but the gameplay is kinda boring. basically formation battle . you put melee guys on front and range guys on the back and support at the middle. and that's it and hope that your melee guys can tank enemies. there's a direct pvp battle option but it's just who's level is higher wins.