I really have no idea how this may change Heisuke's body heat in comparison to that of a human's, but basically, Heisuke's kind of a, uh.. pseudo-demon thing with vampiric qualities? Basically, he has greater strength than a human would have and can stand up to more injuries as well, thanks to his healing abilities. He obviously can't withstand injuries on vital organs like the heart, but yeah.

He feels a lot weaker during the day and in the sunlight too aaaand he gets this "bloodlust" every now and then where he feels he needs to drink blood. During that, he's also a ton weaker as well. For now in Luceti, he's going to be trying to suppress that as much as he can though, even though there's blood available. |D;

...I'm tired so I apologize if this isn't coherent oops. There's some info on it here though.