LOL that is quite the title
Edit: What, and i emphasize, the fuck but dang i wonder if anyone else in the family knows, since the little bro didn't hide his ability? from the friend even if they didn't see his 'other form', but he doesn't seem to want to kill him or so versus just maybe feeding off his energy but i guess if he's some kinda immortal it'll make things complicated (maybe at one point he'll snap and kill himself and the lil bro will 'revive' him)
(almost thought it was by the same person who did the ichinose family manga)