Dubbed as the "Angel of Death," Azrael has a name that literally means "whom God helps." Known with several spelling variations including Azrail, Ashriel, Azriel, Azaril, Gabriel, etc, this angel's name evokes divine mercy more than the idea of dying which is transitional just like any natural transitions in life. This archangel is believed to be tasked to separate the soul from the dead body after 40 days. Among the many roles seen played by this archangel, include helping those who are left to grieve over the death of their loved ones.
Stories about Azrael have fascinated a number of writers such that they even appear in games. In one such online game, In Nomine, by Steve Jackson Games, a "roleplaying game featuring the War between Heaven and Hell," Azrael is featured and described almost as a bane of all the other angels. See the whole story here.
Briefly, in the said game, the story of which looks like a retelling of ancient stories from various sources, Azrael is described, being consistent with old stories, as the one tasked to undertake the final moments of a dying person on Earth. This archangel, in an apparent war among angels in Heaven, has taken upon himself / herself the role of ensuring even up to the last moments the saving of souls. This archangel, with his / her helper angels would even venture into the dangers of going into the realm of Hell just to sneak out souls that should have been in Heaven, all for the glory of God. Accordingly, this archangel, apparently, also seeks out those souls that have been stuck in their present condition as "ghosts" and would not want to transition finally into the afterlife.
Depicted through the centuries as dark and foreboding (mainly because of man's fear of death), Azrael gets to be shown more positively by people who seek out and who call forth the help and intervention of angels nowadays. As such, Azrael is described as "dark, very quiet," and not at all scary. This archangel's actually "the most sensitive and gentle within God's creation" (see this page for additional details). This is consistent with God's trait of enduring mercy, which quality would make the Lord and his assigned messengers (angels) to do everything just to be able to save souls from eternal damnation.
Arabic traditions describe Azrael as "forever writing in a large book and forever erasing what he writes; what he writes is the birth of a man, what erases is the name of the man at death." Also, such traditions also describe Azrael as the one who succeeded in bringing back 7 handfuls of earth for the creation of Adam, which assignment the archangels Michael, Gabriel and Israfel failed to accomplish when tasked by the Lord. This archangel was then given the task, because of the feat, to separate the body from the soul when death occurs in human beings. This mission is apparently extended in other Oriental legends that describe Azrael holding an apple from the Tree of Life to the nostril of the dying person, so as to "bring death first and separation afterward."
Muslims also believe Azrael as another appearance of the archangel Raphael. This archangel is also depicted as having "70,000 feet and 4000 wings, while his body is provided with as many eyes and tongues as there as men in the world." Such gigantic proportions allow this archangel to rest one foot on one of the levels of heaven, and the other between hell and paradise.
Azrael's depiction in pop culture borders on the incredible, and goes far than the stories shared in traditions described earlier. For example, this archangel appears as the opponent, being a warrior/angel of death, of the character "Wolverine" of the X-Men fame "every time he suffers a wound in order to save his soul (which is then returned to his body when he wins). Azrael, as spelled "Azriel," appears also as the main character of Anne Rice's "Servant of the Bones"(a Babylonian young man who was bewitched and killed, and whose spirit now as Azriel obeys the commands of whoever acquires his gold-encased mortal bones).
Call on Azrael when you're in grief over the death of a loved one. Also, seek this archangel's help when you would like to seek divine intervention for the recently dead for peaceful transition into the realm of the after-world.
Main Source (unless when cited in links above):
A Dictionary of Angels (including the fallen angels) by Gustav Davidson, copyright @ 1967 The Free Press A Division of Macmillan, Inc.