Broker

Brokers (協力者 (ブローカー, Burōkā)) are humans who have made deals with the Millennium Earl and sold out their fellow humans to provide the Earl with grief stricken victims to build his Akuma army.

Overview
Technically speaking a Broker is anyone who provides the Earl with information or humans in exchange for money (and possibly other things), though some seem to make a living off of it, the one broker seen, a nun who worked at the Hearst Orphan Asylum, addressing an affiliate of the Noah Family over the phone as "Master".

Reasons for joining the Earl in such a way, presumably, vary, though the one Broker shown called those fighting against the Earl "selfish." She also seemed to be under the impression that, because she supported the Earl, she had gained some immunity against being killed by the Akuma, though she was quickly proven wrong when a Level 2 first turned her into a doll, then crushed her head and used her death to feed itself, showing that supporting the Earl as a Broker in no way guarantees safety.

Trivia

 * Dgray-man-343283.jpg one Broker has been seen thus far in the series; one of the nuns who worked at the Hearst Orphan Asylum where Timothy Hearst lived. She was later killed by the Akuma, who had no qualms with finishing her off when she was in the way, even though she was a supporter of the Earl.