Ga-Rei-Zero

Summary

"Will you kill someone you love because of love?"

The Japanese Ministry of Defense has an anti-paranormal special forces group called the Supernatural Disaster Prevention Office. They are the ones responsible to protect Japanese soil and its people from supernatural and paranormal events. However, things didn't go so well in one of their missions...

(Source: Anime News Network)

This series is a prequel to the manga series, Ga-Rei.