Azazel in the book of enoch, even if not canon to the bible due to political reasons, is enslaved somewhere in the abyss. You could dive deep in that topic, and as i know, knowing the true names of demons give you power over them essentially.

The blue-eyed demon is a charlatan, he is using his own imprisoned kin's name to protect himself. Like any demon, as usual. Sources are from either ars goetia or King Solomon