Sagami

Sagami (鎖上) was a colleague of Kurogane, and the exorcist that previously imprisoned the evil spirit Jaren. Jaren claimed that Sagami called himself "history's greatest exorcist".

History
Ten years ago, Jaren was kept sealed in the basement of a church by Sagami. As part of the ritual to maintain the seal, the stakes imprisoning him had to be exchanged occasionally. Kurogane took over responsibility for this when Sagami became too old. However, in his immaturity, he was eventually manipulated by Jaren's words and tricked into releasing the spirit. Jaren's first act was to consume Sagami, inspiring Kurogane's quest to capture him at all costs.

Power & Abilities
Exorcism: Sagami is implied to have been a very formidable exorcist, and was at the very least capable of restraining Jaren for some time.