Lazaer

Lazaer is a recent addition to Marvel's infinite alter-egoes for Death itself, being primarily a villain of Wolverine and a seemingly eternal nemesis whose origins and purpose are shrouded in mystery.. though Wolverine considers him an "angel of Death".

History
Lazaer is a mysterious supernatural entity residing in a Limbo-esque realm linked to Wolverine, whenever Wolverine experiences a near-death scenario he is taken to this realm and forced into combatting Lazaer, presumably if Wolverine ever lost one of these fights he would die.. so far Wolverine has succeeded in keeping Lazaer at bay but the "angel of Death" always returns, waiting for the day Wolverine finally loses.

Abilities
Lazaer is a divine entity with unimaginable power, most of which have not been revealed - he likely has all the abilities of an angel combined with the abilities of other Death entities, like most forms of Death he seems to be bond by certain rules and conduct, as such his infinite power is limited, if only by choice or cosmic law.

Trivia

 * Lazaer is just one of many alternate forms Death takes in Marvel, being a multiversal concept - some other alter-egoes of Death include Deathurge, the Scarlet Personage and Lady Chaos.
 * Lazaer is also not the only depiction of the "Angel of Death" in Marvel.