Sacred Beast: Twin Dolls 1 - Hentai schoolgirl gives her body to demon lord

Ai and Mai Amatsu are twin sisters, who have been trained by their grandmother Genshu in the family's spiritual traditions. Little do the twins know how useful being preistesses will be when vile creatures from the demon beast world appear to lead mankind astray. The lecherous monsters have an ancient vendetta against the Amatsu family for their part over the centuries in keeping the demon beast world at bay. Things become complicated when Genshu decides to fulfill the family's customary duty early as the guardians of the god Tenjin's descendant, who turns out to be a perverted youngman himself. Caught between the depravity of the demons and their young charge, will Ai and Mai be able to fend them all off?