The Story of Inarius, the 2nd Fallen Angel:
Inarius:
Quite an interesting tale that is, an angel that falls to the dark side (yet chose his own path) not by corruption, but because of his narcissistic nature. Could have been a rescue/salvation-quest just like the ones about Lachdanan & Izual (that would have made 3 Quests about the Light-Faction as opposed to the 3 Quests about Darkness' Finest [Andariel, the Lieutenants of Azmodan+Belial & Diablo)] quite an harmonic result, right?):
(taken from www.lunarfalls.com (@Archive.org) by Nephalim the original version is to be found in the Diablo I Manual)
Inarius was an angel in the Seraphim who prided himself upon his great beauty. He boasted of it to his enemies and allies alike until finally he became so diluted that he believed himself better than his fellows. He left the High Heavens in order to establish a following dedicated to serving him.
Still wanting to prove his power and dominance, Inarius laid siege to a dark temple dedicated to Mephisto. However, the Lord of Hatred would have vengeance for this travesty, and he laid waste to the mirrored cathedral of Inarius. Inarius and his followers were captured.
Using unholy spells and vile surgery, Inarius was altered to resemble an ugly, putrid, bloated demon with misshapen features and greasy flab. His followers were mostly given the same transformation, and they were thereafter used as minions of the Evils, and came to be known as Overlords.
Inarius, however, is said to be still alive, his eyelids torn from his face, locked inside a mirrored chamber in the deepest regions of Hell, to look at his malformed self for the rest of eternity.