Melchior

Melchior (メルキオール Merukiōru) is one of the three members of the Grigori: the supreme advisors of the True Cross Order.

Appearance
Though his appearance is greatly shielded by the hooded ornament that he wears, Melchior appears to be a rather aged male, with a very long silver beard. Beneath the garments, Melchior wears dark robes; from the ornament dangles a light-green veil that is parted, giving one the view of Melchior's mouth, only.

Training Camp arc
Melchior and the rest of the Grigori act as overseers for Mephisto's trial, where Melchior in particular questions the man's reason for keeping Rin Okumura alive. He then listens silently as Mephisto asks him and the other Grigori to make a wager with him about how Rin will turn out: savior of Assiah or Demon King of Gehenna. However, after listening to Rin's outburst and Mephisto's claim, Melchior and the other Grigori prevent Arthur from executing the boy and allow him to live under the condition that he pass the Exorcist Qualification Exam in six months time, among many others.

Academy Seven Wonders arc
Melchior and the other Grigori are later present during Arthur and Lewin's account of what happened in Yemen, where they learn of the Demon Eater and the problems they could potentially bring up in the world. He then remains silent as Balthasar reduces Rin's execution to a suspension.

Melchior and his two other compatriots are later visited by Lucifer's Seraphim and hear the words he has to speak. However, the Seraphim at his location explodes, but he and the other Grigori members are saved by Arthur.

Blue Night Investigation arc
It is revealed during Lightning and Ryuji's investigation of the Blue Night, that the man known as Melchior is merely the public stand-in for Azazel, the King of Spirits who had sided with humanity.

Trivia

 * Melchior shares his name with one of the Biblical Magi.