Nightmare x Deathscythe: Hangyaku no Resonance

Rinne, Setsuna, and Yuuka have unknowingly entered an endless abyss of depravity. Rinne, who inherited the blood of a shinigami, finds herself pregnant with the child of a demon and undergoes a disturbing change within her. Setsuna and Yuuka, too, are surrounded by members of a cult and subjected to sexual torment by a legendary torture artifact. Witnessing the transformations of their two companions, Rinne is also subjected, and when brought to the brink of despair, the mark of a demon begins to appear. At that moment, her true power as a carrier of shinigami blood is fully awakened, accompanied by a brilliant flash.