Many of the skills acquired as characters progress may only be performed in a certain order, or chain. Generally the skills located farther along in the chain are more powerful than those at the beginning, or those that have no prerequisite.
The PvPvE gameplay of Aion revolves around battles within the Abyss and Balaurea (PvP zones). Within these zones are fortresses which can be controlled by individual Legions (the Aion equivalent of Guilds). Battle to control these castles involves combat against players of the opposing faction and computer controlled NPCs at the same time, using siege weapons obtained from PvE raid content. Legions in control of a castle are entitled to funding from taxes and players within the faction get specials from NPCs and discounts for travel and vendor items. The game currently does not allow factions to fight against those of their own race, except for casual duels or in the Arena, or Panesterra.
The participation in PvP is rewarded with Abyss Points in the game. The game ranks players as battles are won against fellow players based on their participation in the Abyss and Balaurea. Certain items can be purchased with these points such as high-end armor and weapons. This is referred to as the Abyss Rank system, and there can only be a limited number of high-ranking players per server. The highest-ranking players compete for the relatively few rank positions available. Players of a very high rank are also granted the ability to transform into what is known as a Guardian General; a form that bestows an exceedingly large boost to certain stats. Abyss points are gained by killing other players in combat, and points are lost by being killed by another player. Higher points are awarded for a kill of a much higher ranked player than for killing an equal or lower ranked player. Abyss Points can also be earned by completing certain quests and by selling certain items.
In 4.5 patch, a new Glory Point system is introduced. It replaced the Abyss Point ranking system, turning Abyss Points into a currency to be spent instead of a factor defines players’ rank. You can get these glory points from sieges or pvp and pve instances. Player cannot get these points from killing the opposite faction. Glory points are not usable as currency to buy new items, but they do decrease a certain amount daily, and the number of lost points depends on the players rank
When the god Aion created the world of Atreia, They created the Drakan—powerful dragon-like beasts tasked with safeguarding the humans; performing Aion’s will on the planet; and protecting the Tower of Eternity, Aion’s physical presence on Atreia. For a time, the Drakan obeyed Aion; but over time, they began to enjoy their power, ignoring their duties and abusing the humans who inhabited Atreia. Aion took notice, creating the twelve Empyrean Lords in response. Angelic in appearance, the Empyrean Lords were demigods who walked amongst humans, and used a force called “Aether” to create a powerful barrier, later to be called an aetheric field, around the Tower of Eternity, protecting all of those within. While the outside world continued to be ravaged by the Drakan, who had become the more ferocious Balaur; the humans within the barrier managed to tap into the Aether, gaining their own powers. In time, they would become known as the Daeva.
As time went on, the Lords decided that they had to be more aggressive in stopping the Balaur. With the number of Daeva growing, the Lords decided to form an army, with ten of the Empyrean Lords leading the Daeva into battle; while the remaining two, Siel and Israphel, protected the Tower of Eternity (thus earning the title “Tower Lords”). This conflict between the Balaur and the Empyrean Lords would come to be known as the Millennium War, which led to no real progress by any side. As the war progressed, a faction of Lords began to view the war as unwinnable, and Lord Israphel proposed a discussion of peace with the Balaur. This surprise proposal drew criticism from within the faction; after a lengthy and heated debate, seven of the twelve Lords became the winning majority to move forward with the plan.
However, for reasons unclear, the negotiation failed. When the Balaur arrived at the Tower of Eternity, a commotion broke out, killing a Balaurian captain; the remaining Balaur, enraged, marched upon and destroyed the Tower, which set off a chain reaction that threatened to destroy the planet. However, Israphel and Siel made the ultimate sacrifice and gave their own lives to protect Atreia. The world was shattered into two “hemi-shells”, with a dark Abyss lying between them; but it was held together by the aetheric field created from the Tower Lords’ sacrifice.
While the Balaur were banished to the Abyss, the Empyrean Lords found themselves in conflict with each other. Two groups were formed as a result, each with five Lords; the Seraphim, who had proposed the peace solution and blamed the others for sabotaging the peace negotiations by failing to agree to them; and the Shedim, who blamed the Seraphim, believing that their weakness and their proposing of the peace talk allowed the Balaur to gain the upper hand. From that day on, the two sides became bitter enemies.
The Shedim migrated to Asmodae, the dark and harsh upper, inner half of the planet; while the Seraphim Lords settled in Elysea, the light and abundant bottom half. They both took their humans and Daeva with them, and over time, they adapted to their respective new worlds and declared the opposing side their mortal enemies. Those in Asmodae became the Asmodians, rugged survivors, gaining dark features and a fierce loyalty to their kin. Those in Elysea became the Elyos, growing even more beautiful and believing themselves to be Aion’s chosen people (although they have grown arrogant). From that day on, they would wage war for centuries as bloody enemies.