Gehaburn

Gehaburn (ジエハバーン Jehaban), also known as Gremory (グレモリ Guremori), Deidarabotchi (デイダラボッチ, Deidarabocchi), or Fuhengareeima Ipponboshi (不変昏影魔一本星, Everlasting Twilit Shadow Demon: One-Legged Star) is an ancient demon that had lived in Earthland long before humans. Feared among humans, it was reputed as a demon that rent the land asunder, and was known for causing many calamities throughout history. As of the current storyline, Jason LaHote defeated it, through what means are unknown. It's soul resides sealed in a blade that bears it's name, a process that happened via ancient magic, one all demons are vulnerable to, bestowing the name of a demon upon someone or something after it is defeated. Due to this, it is technically not "dead", merely "repressed".