Inarius was not actually a member of the Angiris Council during The Great Conflict. He instead served as an advisor to Tyreal, The Aspect of Justice, and aided the angels in their struggle against the three Prime Evils. Renowned for his great skill on the battlefield, Inarius was responsible for defeating Azmodan, one of the Lesser Evils, and nobly defended Heaven against the forces of Hell.

Despite Inarius' personal successes, he became jaded by the eons of conflict, and tried to convince Tyreal that the endless war was for nought. Unfortunately, he believed Tyreal to be too consumed by his lust for war, and was therefore unable to seek a peaceful resolution. Despite his failure to convince the Aspect, Inarius concluded that there must be more like-minded souls out there, who wanted an end to the bloodshed between Heaven and Hell.

During one particularly brutal battle at the Pandemonium Fortress, Inarius' forces were soundly defeated, and the angel was captured by his demonic enemies. Imprisoned by Mephisto, the Lord of Hatred, Inarius was bound in chains, ranting about his desire for The Great Conflict to come to an end. Eventually he was let go by none other than Lilith, Daughter of Mephisto.

She, too, had rebelled against the notion of endless war, and did not share her father's desire to inflict suffering upon all worlds. Transfixed by the first demon to ever agree with him, Inarius fell in love with her, and so they joined forces, drawing to them other beings who longed for peace.