the main guy is adopted when his parents die in a car accident.
His brother is a vampire and sucks his blood when he gets hungry, but he believes that he is a vampire, however his instincts haven't awakened yet. His "brother", the seme stops drinking his blodd because he is afraid he'll hurt him.
The uke's instincts awaken but turns out he is a werewolf, his parents were vapirexwerewolf.
Either way, his so called "childhood friend" a werewolf, that he was friends with when he was a child and still had his biological parents, fins him by his scent and tries to make him his pair, but the seme vampire finds him and gets jealous.
Kaoru Kemono