The Radiance of the Morning Star

After one misstep, the archangel of Heaven is swept into a rift in time and space. When he wakes, he finds humans respectfully calling him "Angel." Is this... the mortal realm? Before long, a group of demons invite him to Hell. Luciferiel wants to return to Heaven, only to discover that this isn't his world at all, but the future, a million years later! The "Luciferiel" of this world changed his name to "Lucifer" and became the King of Hell. Luciferiel suddenly no longer recognizes this world. "He" gave up his position as Heaven's second-in-command and went off to that shabby Hell to become Satan! [Luciferiel x Lucifer] P.S. The archangel tops that harem-having King of Hell!