The fallen leaves tell a story. A story about a young Empyrean, who was on the brink of Godhood, yet felled, as only one God and Lord Consort could exist. As he faded away with his Lord brother, he saw a small, golden flicker, before the light overtook him.
When he awoke, he found himself in a new land, unlike the Lands Between. Finding it difficult to assimilate into the new world, and seeing how much sadness and suffering the people experienced, he made up his mind, his plans unchanged. He would become God, and usher in the Age of Compassion, and make the world a gentler place.
After all, he wasn't called Miquella the Kind for nothing.
(I don't own Highschool DxD or Elden Ring)