Rin is taken away to Gehenna when he is a baby. Unfortunately, they can't obtain Kurikara. The young prince gets raised as a human by Satan and fifteen years later he has to go back and get his demon heart, so he can gain his demonic powers and become the worthy son of Satan.

Just a basic understanding of how my personal universes work! Information on this will be used in future fanfictions!

A story challenge for those interested in writing it. Rin is taken when he's a new born, and raised in Gehenna by Satan while Yukio is still taken in by Shiro Fujimoto. No younger than fifteen, Yukio tries to summon a demon and ends up summoning Rin. Satan is still trying to find a way to emerge Gehenna and Assiah together, and now Rin has to pick sides. More details are inside.

For the first time in a long time, Arthur has finally opened his heart enough to let someone in. And Francis doesn't want to let him down. He has prepared a special night for him, and he wants absolutely everything to be perfect. But unfortunately for him, he seems to underestimate just how impossible perfection is, and how thin his own limitations are. FrUk/UkFr Omorashi

What secrets does England's diary hold? Francis finds his diary and reads it, and is stunned at the content. Only the greatest love the planet has ever known.

[post-anime] After saving Assiah from Satan's plan to unite it with Gehenna, a radical Pope had come to power and now demands Rin and Yukio to be executed for being 'spawns of Satan' - Ever since, the twins found themselves tortured by the Pope's henchmen. However, there was a force they hadn't reckoned with: Satan.. [brotherly RinxYukio SatanxYuri] – Rating will go up.