Some fanfictions pair Azrael with a human who has a special gift, like being able to see the future or communicate with spirits. This human can act as a guide for Azrael in the human world, while Azrael protects the human from the more dangerous aspects of the supernatural world.
It may drive away some of the original fan base. Fans who are interested in the pure, original story of 'Knightfall' may be turned off by the existence of sexual fanfics related to it. Also, it can create a negative perception among potential new fans. When they search for 'Knightfall' and come across such sexual fanfics, they might wrongly assume that the whole franchise is about sexual content, which is not the case for the original work. Moreover, it can also affect the way the media and critics view the franchise. They might be more likely to focus on the negative aspects related to the sexual fanfics rather than the positive aspects of the original 'Knightfall' content.
Azrael in 'Supernatural' fanfiction is often depicted as an angel of death. In the context of the show and related fanfictions, Azrael has powers related to death and the afterlife. They are usually a very powerful and mysterious character.
One key element is his power. He's extremely strong, which drives a lot of the story. Another is his ambition. He wants to be on top. Also, his battles with other powerful characters are important parts of his story.
I'm not sure exactly, but there are several volumes of Knightfall comics. You might need to check with a comic book store or online database for an accurate count.