Slime Master: Total Corruption

A princess knight and eight knightess —the heroines of this story— are corrupted by the forces of evil (You). The protagonist (nameable) can manipulate vicious slimes through forbidden magic and uses them to ravage women in various lands. He sets his sights on his next target: the Kingdom of Xanadoa, where soon a princess knight becomes the king. On his way he happens to murder Lord Claude, a close ally of the former king, and infiltrates the kingdom by impersonating him. Behind the scenes, he uses the slimes to attack the women of the kingdom, stealing their virginity and imprisoning them in a desolate dungeon. One after another the proud princess and her loyal knightess are subjected to mind-breaking pleasure. Eventually, their hearts are completely corrupted.