Azrael, AKA, The Angel of Death, or, Lazaer, is a Marvel Comics villain and an enemy to anyone who denies death's natural rules, like Wolverine.
Azrael is also known as the Angel of Death. He sends souls to the afterlife and murdered people who don't follow to death's natural rules, whether being cheating death or killing people before their time.
If any his opponent somehow managed to kill him, they would fight him again in Purgatory if his opponent died. This is for the chance to escape the afterlife if they won in Purgatory. Most of the people who were able to beat Azrael twice would become trapped in their earth-bound undead corpses. One of the few exception is Wolverine, due to his accellerating healing factor. He thought Mystique was dead so married other people. Most of his sons have the teleportation ability. Rogue is his foster daughter. He is one of the most powerful X men villains.
Many years ago an ancient demonic mutant from biblical times and his horde called the Neyaphem were in an epic battle with a group of angelic mutants, named the Cheyararfim. The Cheyarafim were victorious and vanquished the evil mutants to an alternate dimension for all eternity. Their leader, Azazel, was the only one who was able to breach the dimensional void for brief periods of time due to his teleportation powers. His only hope to return to earth was by impregnating women because his children are linked to his dimension.