Aion: The Tower of Eternity (Korean: ???: ??? ?) is a massively multiplayer online role-playing game (MMORPG) released in Korea with new localized versions in development. The game developer is NCsoft, a major Korean game developer. Aion combines PvP and PvE in a fantasy dream setting. A major feature of the game is flying, both to reach new areas of the game and for aerial combat.

In the beginning there was a god named Aion who ruled over a world called Atreia. This god created a race of intelligent entities to act as his servants (in likeness to angels) whom he called the Balaur. After some time passed the Balaur disobeyed Aion`s wishes and rebelled against their creator. The god Aion then created the 12 Empyrean Lords. The Empyrean Lords in turn created a barrier which prevented the Balaur from attacking the humans charged under their protection. Within this barrier all things were safe. The Balaur ravaged and destroyed many of the living things residing outside of the barrier. Some humans, living within the safety of the barrier, learned how to harness some of the same energy as the Empyrean Lords, known as aether. Such humans were called Daeva and, like the Empyrean Lords, had wings. With time, enough Daevas were born to form an army. Ten of the Empyrean Lords led these Daevas into battle against the Balaur, while the remaining two were the guardians of the Tower of Eternity, the embodiment of the god Aion. The war with the Balaur lasted for hundreds of years until one of the guardians of the tower announced that they should find a way to make peace with the Balaur. Five of the Empyrean Lords vehemently disagreed. However, the second guardian of the tower was swayed to peace. The Balaur were invited into the tower for peace talks. It is unclear what happened at that point. One of the Balaur lords lay wounded on the floor and the rest proceeded to attack the tower. The two Guardians attempted to raise the shield by going to opposite ends of the tower. However, they were unsuccessful and the tower, along with the world, shattered in two. As their final act, the two guardians sacrificed their lives in order to protect a part of Atreia. With Atreia severed, the survivors banded together to face their new world. Of the original twelve, ten of the Empyrean Lords survived. Five who had opposed peace and claimed that the weakness of the rest of the lords had allowed the Balaur to attack them reigned over the dark part of the world, becoming known as the Shedim Lords. The other five reigned over the light-covered bottom part of Atreia and claim that it was the Shedim Lord`s actions that caused the breaking of the tower. They are known as the Seraphim Lords.

The new shape of the world also reshaped its inhabitants. Those that lived in the light part of the world saw little change except for and increase in their beauty. These followers of the Seraphim Lords called themselves Elyos and created the city of Elysea. The inhabitants of the upper part of the world saw many changes. Having to walk on ground strewn with fragments of the tower, their feet became talons. Having to fight against beasts, their hands became claw-like. Furthermore, the darkness made their complexion change and their eyes grew red adapting to the absence of light. They call themselves Asmodians and live in the city of Pandemonium under the rule of the Shedim Lords.

Aion is designed with two playable races: the Elyos and the Asmodians. Both races have the same origin, which explains the fact that they are not that different in their appearance. The most distinctive differences are the skin color and their wings. While some people may assume that one race (the Elyos) is good and the other race(Asmodian) is evil, the developers have explicitly said that neither race can be characterized as either good or evil, but that their motives are much more complex.

A popular feature that has been implemented into Aion is the ability to fly, which can be obtained early in the game. Flying is available to every character (once they reach level 10) and combat while flying is built into the game. Flight is used by the players to find locations and materials that are not accessible through walking on the ground. Initially when you receive the power of flight your character can fly only for one minute at a time. As characters gain levels, they can fly longer, and fly faster. There are also items that increase flight time and flight speed.