Semele The Good Villain

Semele was just an ordinary 12 year old boy is ambushed and taken to a secret room and put to sleep by a man with emerald eyes a mask and white suit when he soon wakes up in a hospital bed his aunt in a chair beside him he's befuddled until he gets told he passed out on the way to school is that really the case? The mark on his right wrist says other wise.