Ib׃ Instant Bullet

ib: Instant Bullet (ib -インスタントバレット-) is a manga series by Aka Akasaka. It was serialized in Dengeki Maoh.

Plot
Fukase, an outcast, a loner, a yankee has had enough of this world. He wants nothing to do with it and silently wished for the world to end. Yet during Christmas Eve, a chance encounter with an unknown creature and a girl named Sera may change him and his fate.