Fenrir

Who is this guy? tune in next week to find out!

that's what you get for getting invested.

Spoiler's for those who havent seen it yet

As Fenrir's true identity is made known, it's revealed that the tattoo possessed Kazuma three years ago and sealing it with Cat-sìth was the only way to keep it in check. Eiji's death weakened the seal and Fenrir reveals another shocking truth.