The newly appointed Paladin. He was ordered by the Grigori to to interrogate Mephisto and captured Rin as evidence. According to Shura he's a saint on the outside and a devil inside. Uses the demon sword Caliburn.

Appearance
Angel has long blonde hair in a pony tail, with a communicator in his ear, though it is unclear whether or not he wears it all the time. He wears a fancy white suit that is custom made. Rin makes fun of it.

Personality
Not much is known about Arthur so far, except that he is extremely loyal to the True Cross Order. He follows the orders of his superiors without questioning them at all, even attempting to kill people when they interfere with his work. He believes that anything related to Satan must be destroyed, as it could only cause harm to let them live. Arthur also seems to be slightly sadistic, as he stabbed Rin completely through the leg to immobilize him during Rin's trial, while remarking that the wound would heal soon enough. According to Shura, he is a saint on the outside and a devil on the inside, hinting that he may have a malicious personality.

Powers & Abilities
Despite not being seen in combat, it can be assumed that Arthur is extremely powerful, as he was given the rank of Paladin, which only the strongest exorcist in the world can hold. He wields a demon sword, called Caliburn, indicating that he obtained a Meister as a Knight.

His power is hinted at when he was quickly able to overcome Kirigakure Shura, one of the most powerful exorcists seen in the series.

Caliburn his demon blade, seems to be able to talk, and has the personality of a little girl who adores Arthur. He's willing to cut some of his hair, using Caliburn, in exchange for power.

(Source: Ao no Exorcist Wikia)