Original title: 闇染Revenger －墜ちた魔王と堕ちる戦姫－
Kazunori is an extremely normal student. However, his soul became linked with the demon king Criveherz, who had committed all kinds of impudent acts in another world and was being chased by the Goddess Fein. Determined to vanquish the demon king once and for all, she sent heroines from the other world to continue chasing them.
Even though Kazunori was worried about his future, the demon king reassured him that their pursuers are also weakened in this world and that he will use his powers to make them into his own harem. Kazunori was attracted by the prospect of having a harem, but his life has surely been turned upside-down!