Asmodeus is a demon.
The good news: He doesn't answer to God.
The bad news: He transmigrated to a world that does.
After transmigrating here centuries ago, Asmodeus was thoroughly fed up with this chaotic universe, with its tangled pantheon, exploding planets, Gaia and Alaya constantly bickering, and the Throne of Heroes always trying to suck him in.
The good news again: He finally found a way to leave this universe.
The bad news again: Before leaving, he accidentally slept with a young believer of God, who then died saving someone shortly after he was gone.
Holding the young believer's serene-looking head, Asmodeus, on an impulse, used the power he hadn't touched since transmigrating.
As a result, he successfully left this chaotic universe with the young believer's true self from the Throne of Heroes.
Looking at Asmodeus, who had golden blood running all over the floor, and the ring on his hand stained gold by the blood, Amakusa Shirou sighed helplessly.
"Mr. Demon, what have you done?"
"Nothing."
Asmodeus blinked. His long tail curled around the young believer's waist and pulled the unsuspecting boy into his arms.
Blocking out Alaya's distant curses as they came through the worlds, he smiled and made an offer Amakusa Shirou couldn't refuse.
"Would you like to explore the chaotic universe with me and save more people suffering in other worlds?"
Demons don't understand love. Demons only know this:
He wants to claim the young believer he lost and found again as his own.
Reading notes and warnings
[I'm absolutely against breaking up my ship. My top has no sexual relationships with anyone else, thank you very much.]
▲ A few secondary pairings will be mentioned (WeiLan, Gojo x Geto).
▲ My take on Asmodeus uses the six great demons of Zoroastrianism: an immensely powerful demon who is both good and evil.
▲ The Fate setting is merely a backdrop, as is the Hebrew mythology in the Fate universe.
▲ Lots of original worldbuilding.
▲ Slow-paced transmigration.
▲ I reserve the right to have the final say on the story.
Theme: Change the world with true feelings, and save the future with true love.