Kijoku: Princess Double Kari

Based on the erotic game by Nel.

After losing his mom with a mysterious death, Distol swore to himself that he will be the greatest swordsman on the globe. However, his tragedy doesn't end there...Eight years after his mother's death, more bad news is brought to Distol. His sister, Princess Qoona, is chosen since the Holy Maiden. The Holy Maiden sacrifices her own life to offer chance to the seal that binds the demon king within. Normally, this would be something are proud of, but Distol doesn't wish to lose somebody else he loves.

As Distol curses himself for the inability to protect the individual that he loves, a witch appears out of nowhere and bakes an offer to Distol. The sale is: "In exchange of giving great powers, you must invade Bastarauge, make nation's treasure, kidnap Princess Elena, and corrupt her from the inside.In . A whole new dark age will begin...