All the characters in this story are villains to the human race. Azrael is one of the 2 other main villians in the story. 

Broken to her basic components she is creepy and mysterious, she is hidden from the world and talks to Michael through visions. She speaks mainly in riddles and treats herself as a higher being more powerful than Virus or Asteria. 

She is the embodiment of the fear and hatred of humanity. Her name has two meanings, angel of death and angel of god, a helper who knows the fate of mortals. The name is merely a reference as i am not actually religous, but she does know the fates of humans. She was created by cult, it consisted of many roboticists and scientists who didn't understand what they were creating. They all had the same visions and driven mad by power, created her. There's no true way to know why or how she was created with the powers she has. Be it some real higher being or the ravings of mad lunatics engraved into her code. They still were connected by the visions they had.
She does not really know what lies beyond death, she talks like she does to strike fear into others. She only knows as much as the humans knew, and they didnt.