- "Old mankind whom Pluto could not defeat, thou art wickedness which violates the dispensation of the universe. The dispensation of the universe is collective. There must exist nothing that standeth in violation. I shall commence purifying the land."
- —Ancient of Days, Shin Megami Tensei IV
Ancient of Days (エンシェントデイ, Enshentodei) is a demon in the series.
Named after Ancient of Days, he is one of the many names of God. It is a name that is meant to represent that God is eternal in Judaism. In Christianity the name is associated with God, the Holy Spirit, Jesus, and Adam. In Hinduism the name is associated with Kartikeya, and in Buddhism with Brahma and Sanat Kumara.
Shin Megami Tensei IV
In the "Ancient One of the Sun" DLC, following Pluto's defeat at the hands of Flynn and his group, God sends His avatar, the Ancient of Days, to succeed where its predecessor failed. It attacked the remnants of human civilization, destroying what remained of Blasted Tokyo and forcing the survivors to relocate to Pluto Castle.
The White summons Flynn to Blasted Tokyo, intending to show him the despair of the human race. Pluto Castle is attacked by Ancient of Days, prompting Flynn to do battle with it. The Ancient is at first nearly invisible; Burroughs can't even correctly scan him, only getting error messages. She comments it seems as though the Ancient, like Sanat, isn't made of matter native to Blasted Tokyo. It states its mission is "the dispensation of the universe", and insists the old humanity must die to make space for the new one. Halfway through the battle, Kiyoharu runs outside, overjoyed, believing that God's messenger has come to free them from suffering. It makes it clear that it is there to destroy mankind, crushing what little hope he held on to for the last 25 years.
After it is defeated, God speaks to Flynn and Akira, telling them that the former has only defeated one of His forms, and that such trifles will not sway the fate of the world from its course. As multiple cocoons descend from the sky, He tells them that the new humanity will descend upon Blasted Tokyo, and that Genesis has begun. Akira decides that he will negotiate with the new species to seek co-existence and bid Flynn farewell.
The Ancient of Days will only begin using Diarahan if either of its weaknesses - to Elec or Force - is exploited.