爆裂乙女SEXYマリィ

In Shinko Cosmo-Frontier Academy city a young woman suddenly disappears. Then dormitory gets attacked by "Hectocylus" devils. Main character takes the decision to transplant the seed of evil to gain superpowers one of the victim girls. As a result the girl becomes Sexy Mary and fights evil forces with the ways she can.

[From vndbreview]