G-senjou No Neko (Yaoi)

From Aerandria Scans: Shirotae is a beautiful girl with some kind of past. When she transfers to Sagaouka Academy, where her uncle is the director, there is a system called the “princess system.” Shirotae is made the princess, but...?!

"We are all influenced by the moon..." Nao is a pickpocket, stealing money so he and his sister Akira, who suffers from lunatic breakdowns every time the moon becomes full, can live. But which one of them is really affected by the moon?

Alice attends an all girls' academy where all the students are required to live in the dorms. One day, in the dead of the night, she meets a boy--a devil who lives on secrets. Alice carelessly makes a contract with the boy and becomes a witch. Now, she will have to gather secrets for her master...!