Father Azrael

Father Azrael is a powerful Seraph who claims responsibility for "birthing" the Reapers. How true this interpretation is, is currently unclear. However he does refer to the Reapers as his children. Curiously this is not unique to Azrael, as the Child also referred to Sorin as a "Child of Light". Considering that Seraphs are higher beings, it is likely that the parent-child phrasing is more symbolic than literal.

Personality
At first glance, Azrael appears genuine and paternal, but as time goes on, his mannerisms start to seem more creepy and double-edged. He appears to be working with the Church, and declares that he is loyal to the Reapers, however whether or not this is true remains to be seen. He seems to have a lot of authority within the Church, as he confidently gives the Reapers orders.

Amelia Arc
Upon entering the Sol Cathedral, Sorin came face to face with Azrael's beastly form. Sensing her apprehension, Azrael tauntingly asked if Sorin would kill her own father. Upon questioning him about her past, Azrael took great amusement in speaking in riddles, confusing Sorin further.

Azrael tempts Sorin into doing a mission for the church in exchange for information on Kalia. Azrael also promised to restore Sorin's memories for her, and appears to know the details of her past.

Powers and Abilities
Azrael's claws and teeth appear quite capable of killing an opponent. Aside from that, he appears to have the ability to induce crippling headaches, a power he used against Sorin to stop her from attacking. It is unknown if this power only works against Reapers or not.