|“||Not even death can save you from me!||„|
Diablo is the Lord of Terror and leader of the Great Evils that rule the hell. He is the titular main antagonist of the computer game series of the same name. He is known as the Lord of Terror and is one of seven siblings who collectively make up the "Satan" in Diablos setting: Diablo himself has appeared in every installment in the series and is considered a mascot of sorts for the series.
Diablo 1Diablo ruled the hell for ages alongside his brothers during The Great Conflict, but was betrayed by some of them along Baal and Mephisto. As revealed in Diablo 2, however, before their overthrowal, they captured Izual, an angel that sent his forces to attack Hell. From Izual, they know about secrets of Worldstone and it's shards can be used as Soulstones. With this vital information, they willingly let themselves banished to Sanctuary, which then imprisoned by a order of warriors known as the Horadrim, which they had planned all along. Diablo spent two centuries slowly corrupting the Soulstone that imprisoned him thanks to the information from Izual. In time, he was able to extend his influence into the surrounding area and also influence both King Leoric and use his archbishop, Lazarus, who secretly served him as well.
The King proved too strong to fully possess, so the Demon took his son, Prince Albrecht. Then Diablo immediately orders Lazarus to painfully brainwash the king that went insane by what Diablo done, which also made him vulnerable. After brainwashed the king, Lazarus then turn him into the Skeleton King that obey his commands. Diablo then began to shape an outpost of Hell within the catacombs that ran beneath the town of Tristram. By spreading terror into the surrounding countryside, the Demon was able to attract many heroes who came to cleanse the land of evil. By the time the strongest of these heroes, which is actually long lost Prince Aidan, older brother of Albrecht reached this goal after destroyed Lazarus and his former father. Though, he had become fully influenced by the power of Diablo because horrified that his brother was used as Diablo's vessel. In his twisted state, he believed that the only way to fully control the Demon was to plunge Diablo's Soulstone into his own head. This, of course, was exactly what Diablo had planned as the Demon now had an even stronger body to use to find his brothers and complete his ultimate plan that he formulated with his brothers long ago...
Diablo 2Diablo, after struggling with the adventurer's soul for some months, manage to take complete possession of his body, starting his quest to reawaken his brothers. As told by Adria in Diablo 3, before he start searching, he manipulated the adventurer to met Adria and recruit her as his servant. Then, before went on separate way, Diablo impregnated Adria so she can prepare a spare vessel should his present plan and his part of that plan failed (as well as bestow her a power that enable her to discard her humanity physically and mentally in order to become a pure demon with immense power as revealed in Reaper Of Souls). Here, it's revealed that his and his brother's banishment were actually all a set-up, as their plan were to be imprisoned all along in the soulstones, as they would be able to reach the Worldstone, a celestial artifact of enormous power, thus using the heaven's power against themselves. Izual, the fallen angel that met by another heroes, reveal this as well. Diablo, whom eventually fully possessed Aidan and use the moniker as the Dark Wanderer, traveled throughout Sanctuary and managed to release his brothers, Mephisto and Baal from their confinement. Once reunited, Mephisto opened a portal leading to Hell, so Diablo could reclaim it and start a all-out attack against the heavens.
Unfortunately, Diablo was defeated by the new band of heroes and his soulstone destroyed. But he and Mephisto able to give Baal some time to corrupted world stone, which prompt Tyrael to destroy it, as well as have a spare plan with Adria as his new servant.
Diablo 3Diablo returns in the third installment in the series, this time with a slimmer form rather than his previous muscular body as side effect of using a female vessel. It is revealed that Deckard Caine's niece, Leah, was the daughter of Diablo and served as his host. Upon the deaths of the last two Lords of Hell, Belial and Azmodan, Diablo took control of Leah's body and mounted an assault on the High Heavens thanks to Adria's manipulation (which from there became one of three main antagonists in Reaper of Souls along Malthael).
This time, however, he had obsorbed the power of the Black Soulstone given by Adria, the artifact used to imprison the Lords of Hell, effectively becoming the Prime Evil. Although his human body had been severely injured by Imperius, Diablo deforms Leah's body so he can challenged the Angel in his true form. He impaled Imperius with his bladed arm and tore down the gates into the High Heavens, where he attempted to corrupt the Crystal Arch. Unfortunately, the nephelam hero, who track him from Sanctuary managed to defeat his servants and met him at the Crystal Arch, where a final battle took place. In the end, Diablo was destroyed and consumed by the Black Soulstone, and both the stone and his corpse were tossed off of the High Heavens. The stone, however, founded by Archangels when the Heaven recovers.
Reaper of SoulsDespite the destruction of his vessel, his vengeance over his loss still burns, as he ended up trapped in the Black Soulstone. Despite this, he able sent Adria a vision of his return.
His soul, along with his siblings' eventually freed once the battle between Malthael and Nephalem heroes ensues. During the battle, they were absorbed by Malthael to defeat the hero. But Malthael was defeated, and his essence freed in process.
It is said that of the Three, Diablo is the most creative and farsighted of them, perhaps of all the Great Evils. He is calm, cunning, and patient. He sees himself as an artist of terror as fear is his trump card. He knows that conquest comes when enemies turn their back on fear rather than face them. However, Diablo does not acquire his satisfaction from conquest itself, as Mephisto might. Diablo feeds on the terror that preceeds the conquest. To him, the fear a victim has is a greater reward than the pain they suffer when they are actually tortured.
It's also said that due to his power over fear and terror, was so immense and it was that power that also made him unable to feel fear (or rather true fear as he still capable of feeling agitated when Nephalem hero outsmarted him) and it was this ability which Deckard Cain said it made him the most deadly prime evil.
Like his fellow Great Evils, he is confrontational.