Goraihou Gakuen e Youkoso!

Goraihou Academy—A world leading bourgeois school where mysterious creatures gather. In order to protect the academy, the members of the student council with attractive appearances and fickle personalities stand up to…?!

We meet Sakuragawa Shinya, Goraihouji Tadato, and Mashiba Naoki. Handsome and talented Shinya is more or less the main character. Together with Tadato, the president of the student council whose father also happens to be chairman of the board of directors for the school, and Naoki, who is always hitting on an uninterested Shinya, Shinya discovers the haunted secrets of Goraihou Gakuen.

Things begin to change when a dark creature is discovered hiding within the school. The trio go to investigate and find Gen-san. And from there on they solve mysteries and hauntings and other paranormal events within the school.

(Source: Aerandria)

Included one-shot:
Volume 3: Machinaka no Santa Claus-ten