The user of this power can become the embodiment of death itself. This means that they can easily kill others, collect their souls when they die and take their souls to the afterlife. They could also bring about the apocalypse, causing deaths by the millions, possibly even billions. They can decide where a soul will go after death.
The Black (DC/Vertigo Comics) also known as The Rot, is the force of decay and death that affects all life within the universe.
Parliament of Decay (DC/Vertigo Comics)
Death of the Endless(DC/Vertigo Comics) is the supreme and true death in the DC/Vertigo verse, all personifications of death being merely aspects and forms of herself.
Nekron (DC Comics) is the Lord of the Unliving. A cosmic force for evil, he has frequently found himself in conflict with the Green Lantern Corps. During Blackest Night, he has been revealed as the mastermind behind the Black Lantern Corps.
Azraeuz (DC Comics) was the avatar of Death, whose coming was foretold in the Bible of Crime.