The Edyrem were the next generation of the Nephalem and were normal people until converted by Uldyssian. Uldyssian awakened their latent powers, and fought beside them in the Sin War. The main goals of the Edyrem were to bring the Triune and the Cathedral of Light to justice, and despite sustaining heavy losses, they eventually defeated both Lilith and the Veiled Prophet Inarius. Breaking both's power and influence over humankind; perhaps forever.
While the Angiris Council agreed to spare Sanctuary and its mortals. All the Angels except Auriel desired for mankind to start at its beginning; by removing all the memories of the Sin War from the minds of the Edyrem, including the true fate of Uldyssian himself; with only Mendeln being spared due to Trag'Oul's subtle interference.