A kid with a cursed arm that wants to eat everything he touches has to figure out if he's still himself or if the thing inside him is already winning. The show doesn't waste time on "will he lose control" , it starts from the assumption that he already has, and everything after that is just survival and small, brutal acts of defiance. Every fight is a negotiation between a person and a monster wearing his skin, and by episode three you stop asking which one is really talking.
Ban Shen Zhi Jing is a action and fantasy ONA.