Mikakuninkei Crypto Heart

Mikakuninkei Crypto Heart (未確認系クリプトハート, lit. "Unidentified Crypt Heart") is a manga series by Kotarou Mori. It was serialized in Dengeki Daioh.

Plot
Serious high school students, Mashima Yuma of merit, meet a duo of maid. One day accustomed to life in the new school, and de the mysterious girl hunt biological and secluded life of mystery beast (Kuriputiddo). Identity of the girl, Yuma coming to know that it is the same person as the pretty little girl, Enuma picture Kurisu met in the school -?