Aion: The Tower of Eternity is the tale of three races, though only two are playable. The game takes place in a world that has been shattered. On one side of the abyss is the realm of the Elyos, a haughty race that bears some resemblance to angels. On the other side are the Asmodians, with wings made of leather and dark feathers. The races, though descendents from the same people at one time, are at odds with one another, and the war if battled in the abyss.
There is a third non-player faction that can also be drawn into the conflict.
Early in the game, each of the player races can run a quest that will allow them the use of wings.
During a recent event in San Francisco, NCsoft allowed some hands-on time with the game and supplied the following story, which details the lore behind the ascension quest that results in growing wings.
The Asmodian Ascension Quest
The chance to earn your wings and become a Daeva comes relatively early in the life of every true Asmodian, though the path itself can be hard and somewhat mystifying. As you reach level 9 you discover that you must find the Asmodian known as Munin, who has been detained deep within the Ishalgen Prison Camp.

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Trapped within a crystallized prison cell, Munin is your key to Ascension. This Daeva can discern the future, even trapped in his cell. This expert fortuneteller will be able to tell your future and how you will ascend to be a mighty Asmodian, but first he needs items that can help piece together your past. He will need these items, the cards of fate, from three different disciples in order to proceed.
The first appears as an old tailor by the name of Urd, who resides in Aldelle Village, which you should already be familiar with as it was one of the first places you would have passed through as a young Asmodian. Urd gives you a card that represents your past "I see two twisted creepers" and sends you to the next disciple, the Old Lady Fortuneteller.
She lives out in the Munihele Forest, located roughly halfway between Aldelle Basin and the Prison Camp. You can find her near a small log cabin, well off the beaten path, where she goes by the name of Verdandi. The hermit will read your palm and gives you a card of fate detailing your present state, though you are warned you will not understand what it means (though Munin will).