Butterfly Kiss Blade  

Ｂｕｔｔｅｒｆｌｙ　Ｋｉｓｓ．ＢＬＡＤＥ, バタフライキス

At Principia Academy, two students named Homura Tsukishima and Sakurako Hirosue share a room. The academy is situated on an island dedicated to studying the phenomenon known as "shiki," which involves harnessing numerical energy for various purposes.