There are supposedly two ways the archangel accomplishes this. According to one legend as described in A Dictionary of Angels, Including the Fallen Angels, Azrael lures the soul of a righteous person by “holding an apple from the Tree of Life to the nostril of the dying person.”
The other way is far less amicable. The Book of Angels states Azrael rips out the souls of the faithless before turning them over to Michael.
In Hebrew and Islamic lore, Azrael is the angel of death. A Dictionary of Angels recounts a Persian myth in which Azrael provided “seven handfuls of dirt for the creation of Adam...and because of this feat he was appointed to separate body from soul.”
His name means “Whom God helps” and he is the ruler of the Third Heaven (Shehaquim). According to Islamic angelology, Azrael is “another form of Raphael, and possesses 70,000 feet and 40,000 wings. He has as many eyes and tongues as there are people.” (The Encyclopedia of Angels). A variation on the apple legend has Azrael writing and erasing names in a book. The writing of a name indicates a birth; the erasing, a death.
Variations of his name include Azra’il (Islamic), Ashriel (Syriac), and Azaril (Aramaic).
Davidson, Gustav. A Dictionary of Angels, Including the Fallen Angels.
New York: The Free Press, 1971, pp. 64
Guiley, Rosemary Ellen. The Encyclopedia of Angels.
New York: Checkmark Books, 2004, pp. 62
Thompson, Ruth; Williams, L.A.; Taylor, Renae. The Book of Angels.
New York: Sterling Publishing Company, Inc., 2006, pp. 96, 98-99
In Death Sword, Azrael is the mysterious archangel of death who supposedly exiled himself and cut off communication with the other angels. However, he establishes contact with Karla Black, the half-human angel who will eventually take his place. Azrael is unconcerned about his fate, entrusting her to continue his duties.
Although Azrael can travel freely, he remains on his island of apple orchards. Each apple represents a soul and, when it falls, that person dies. Because Samael had threatened to overthrow Azrael and take command of his island if he ever left, the archangel of death chose to remain. While only the dead can access his domain, Karla is given special privilege to interact directly with Azrael. The only other angel who sets foot on the island is Samael, although no one knows how he accomplishes this.
Azrael shows Karla visions of Samael destroying Louisville, although she questions whether or not he can see these same images. His eyes are silver but there are no pupils. Nevertheless, he maneuvers about the island without any assistance.
When Karla incarnates as Azrael, she is imbued with his memories, intelligence, and experiences. This enables her to adapt quickly to the halberd which becomes her weapon, much like Xariel’s schiavona and Gabriel’s scythe. Like Xariel, her wings are black and her green eye turns blue, thus signifying completion of her angelic transformation. Like the other angels, she can disguise herself as human. Later in the series, she learns the truth about her parents and her destiny.