Drake Bloed is a member of the dragon killing organization, Tueursdedragon. He is the number one member of the organization, and he is loyal to their leader Gjaku Dragoi, although he may act like an immature kid sometimes.
Why He Joined Tueursdedragon
Besides the fact that hundreds of years ago, dragons kill several humans, Drake joined this organization because his village was destroyed by a dragon. His entire family, as well as all of the citizens, were killed, except for Sarah Impotente.