TV-Series
Description
Yazen holds the position of high priest within the Dangaishuu, an organization devoted to spiritual research and experimentation. His defining ambition is perfecting methods to transmute demons into humans, fueled by the singular goal of converting his beloved fox spirit, Kuzunoha, into human form—a pursuit that shapes his scientific endeavors.

He presents as an elderly man bearing a priestly aura, though severe injuries later deprive him of his right arm's function and right eye's sight. His intellect and resolve coexist with genuine warmth toward allies, yet he readily embraces morally gray choices to further his research or shield those close to him.

Decades before the central storyline, Yazen crossed paths with Kuzunoha during a mission to eliminate potent spirits. He experienced instant love, sparing her life and deceiving his superiors with false claims of her defeat to conceal their clandestine union. This bond irrevocably redirected his life’s course, with Kuzunoha remaining his steadfast companion.

Yazen commands the Spiritual Awakening technique, activated by ingesting Kuzunoha's blood. This transformation grants him nine dragon-headed tails that strike independently, augmenting his physical might, enabling flight, and bestowing abilities like life-force absorption, force-field generation, and illusion casting. His combat potency escalates to mountain-destroying force with FTL+ speed, allowing clashes at parity with adversaries such as the nine-tailed Jinka. Beyond battle, he excels in curse manipulation, soul transplantation, and biological modification—skills evidenced by embedding thousands of souls into soldiers and engineering constructs like Resshin’s curse-based form.

As Part 1’s principal antagonist, Yazen steers the Dangaishuu’s experiments while mentoring figures like Jinka Yamato in spiritual arts. His manipulations include tricking Jinka into believing he murdered Tama, catalyzing Jinka’s spiral into insanity and evolution into the Thousand-Tailed Beast God. Post-Part 1, Yazen vanishes, later surfacing as a captive of the Mountain God. Under coercion, he investigates ways to revert Jinka to humanity.

After escaping imprisonment, Yazen endures near-fatal wounds returning to the Dangaishuu, losing his dominant arm and eye—injuries that permanently terminate his research capacity. In his final acts, he transfers Jinun and Douren’s spiritual cores into Senya, honoring their dying wishes. His tale closes with a decline into fatal illness, tended by Kuzunoha until his passing. Kuzunoha’s subsequent fate is unrecorded.