His family was killed by the Pure Blood. Eight years after that incident, he has joined the International Security Section (ISS) as one of the 12 Apostles. He wields a pistol and is an extremely skilled marksman, he can move swiftly and quickly behind his enemies and dodge attacks. The reason for this is because he trained hard to become strong enough to slay the Pure Blood. Even though he is said to be unapproachable while wielding a gun and has a tragic past, he is still a kind and loyal person. He is also said to be a neat freak, tidying up the paperwork that piled on his desk and aligning them perfectly. when Gilles finds out that Luna is the Pure Blood, he immediately tries to shoot her as he can never forget that she killed her family but he is then stopped by Rett who states that Luna wanted to help get rid of all the vampires, and that's why the ISS is cooperating with her and hidden her real identity. However she is still a vampire and gives Gilles the mission of keeping an eye on her, if she betrays them he can kill her, if she succeeds in getting rid of her brethren he can do what he wants, if he accepts he will become an apostle, knowing this will give him the chance to kill her he accepts the mission becoming an apostle