Who is Cobra from "Fairy Tail"?

In the manga and anime series "Fairy Tail," Cobra is a member of Oración Seis, which is a dark guild composed of highly powerful mages. Cobra is a man with Dragon Slayer lacrima implanted in his body.

Cobra is capable of breathing clouds of toxic gas and transforming his hands into venomous claws. His hearing is hyper-sensitive, which allows him to hear others' movements and read their thoughts. He is usually accompanied by a huge snake named Cuberios, whom he considers to be his only friend. He and the other members of Oración Seis want to find a destructive magic power called Nirvana that was sealed long ago.