Cobalt, a friend of Leon, and living in the Roux home. Born to a middle-class family, he lost his mother and father when he was only age ten. With no other family willing to take him in, he and his sister had been thrown into the slums of Paris. There, he had met  Leon and began to live together. The three would find an abandoned "house" and live there, where Cobalt became sickly and weak. Him, mostly silent and weak, has begun getting treatment by Doctor Bline in the Roux Mansion.

Long brown hair, pulled into a loose ponytail, green eyes,  and pale skin is what he looks like. He is often seen wearing what he had left of his fathers. Long brown shorts and baggy top. Though he has a newspaper boy hat, he never wears it.