Azrael

"YOU HAVE A HIDDEN AGENDA! Only filthy traitors have hidden agendas and secret circles and ominous hoods like you creeps do!" Azrael is the Chapter Master of the Dark Angels and is the most paranoid of all the Dark Angels, executing and/or accusing anyone he suspects to potentially knowing about, or aiding the Fallen.

Official Canon
As Chapter Master, Azrael was given the title Keeper of the Truth and now sits as the head of the Inner Circle, and leads the hunt for the Fallen. He is also privy to the greatest secrets of the chapter, that he alone has the responsibility to bear, and knows the full details and truths behind the Rock’s greatest prisoners and the Fallen.

At some point during his time as Chapter Master, Azrael managed to capture Cypher. Cypher told him that Typhus and Fallen Captain Astelan were conspiring to find the three time-altering Tuchulcha engines, one of which was hidden on The Rock. During the event, due to vague orders on Azrael's part, Ezekiel accidentally scatters the Fallen both in the present and those who were present on Caliban ten-thousand years prior.

TTS Canon
Azrael appears at the conclusion of Season 2, whispering secretively about definitely not heretical topics on The Rock, with Asmodai and Belial. He reacts surprised on seeing two Dark Angels Space Marines interrupting them and confirming they had picked up the trail that had lead them to Orior. He violently beats his Watcher Snurko for mentioning Cypher and later begins to worry that the Inquisition will discover that they have chopped up an inquisitors body and donated the parts to the food rations of a Death Korps of Krieg Regiment, but eventually yells at Asmodai for wasting time, saying they need to capture the Fallen. Upon hearing that the Adeptus Mechanicus got there first, he becomes worried that they are working for the Fallen. After being asked what the Fallen were by two nearby Dark Angels, he had Asmodai make 'them repent'(Murder them violently).

He later yells at Asmodai for asking "are we there yet" during their trip to Orior's surface.

When reaching Orior, he quickly demanded to meet the head of the Mechanicum there and when he is not satisfied with Delphan Gruss' answers, he almost accuses them of working with Fallen, but stopped himself and then declared that they had a hidden agenda. He promptly placing Orior under quarantine, banning any ships to arrive or leave and promptly goes back to the strike craft with the intention to head to Mars to confront the Fabricator General. However on the way back to the ship he is met by Cypher, who casually asks if he has anything to eat on the ship. Azrael perfectly calmly tells him they do, assuming he is another Dark Angel, and tells him it's next to the Pole Dance Quarter.

Eventually he reaches Mars and confronts The Mechanicus Lord for answers, and eventually starts condescending into questioning his legion's ways only to sic Asmodai upon The Omnisiah's Voice upon seeing The Secrets of The Dark Angels Chapter book [which was thrown to the FG by Cypher as a modus operandi for a prank].