I don't know exactly who the main characters are without reading the novel. But it's likely to be the renegade angels themselves.
Since it's a 'Renegade Angels Novel', there are probably a few central angel characters who have decided to break away from the norm. There might also be some supporting characters, like other angels who are either sympathetic to their cause or oppose them vehemently. Maybe there are also some human characters involved, if the renegade angels have some sort of connection or mission related to the human world.
In the 'Renegade Angels Novel', the main characters are most likely to be the angels who are considered renegade. These could be angels with distinct personalities. For instance, there could be a leader among them who is brave and determined, spearheading their rebellious actions. There may also be an angel who is more hesitant at first but gradually becomes more committed to the cause. And if the story has a broader scope, there could be angelic authorities who are trying to stop the renegade angels, and they too could be considered important characters in the narrative.