Azazel used to be Lucifer's right-hand man (demon?) and, it is supposed,  steward. Lucifer is not known for trusting anyone but, for some reason, he trusts Azazel.

This is what makes Azazel's continued absence all the stranger. The Fallen has not been seen or heard of for close to two hundred years. We are assured that he is not in Sheol and has no reason to end up in Tartarus yet, we would have heard, such punishments always receive publicity.

Cruel and twisted is how most people describe him. "As cold as a whale's p-" Asmodeus was allowed to begin before Lucifer stopped him. Stone cold killer is a good description though. He does not enjoy killing, they say for he does not enjoy anything at all. Many today would call him a narcissistic sociopath, perhaps. It used to be that one would simply have to hint that he was coming, that would be enough to make anyone behave.

Abaddon may be a great enforcer and torturer now but even he could not stay and watch Azazel at work. It is supposed that being the scapegoat, he is blamed for everything already so might as well free himself from all responsibility, right?

One thing for sure is that many breathe more easily in his absence.