Mahou Shoujo B-ko

B-Ko is a princess from a magical dimension, who is having a vacation on the earth, masquerading as a student in the Catholic St. Rapahel High School. This peaceful (and pleasant) time-passing ends when the evil witch Saprinu appears in our dimension and attacks B-Ko. Saprinu's demonic plan is to steal precious energy from female virgins. Now it's time for B-Ko's faithful servant, a young man known as Alpha, to "intercept" the poor virgins (using his own methods), before they fall prey to Saprinu...

[from MobyGames]