User blog comment:SpookyBoogie27/Light Novel Spoilers/@comment-67.176.158.104-20140517190942

Could Irina's father have been the one who killed the devil that was residing in their town before Rias. I remember reading that Irina's family had a holy sword in their possession and the devil vanished during the time they were their. And they still haven't explained why they left the town.

Based on some of the quotes someone is going to try and destroy all the supernatural beings that reside their which could be Irina's father.