Inatika Akitani, known as Master, is the human Swordfish Knight, over five centuries old. His animal partner is Zan Amaru. Born in feudal Japan, a near-fatal childhood incident connected him to the Akashic Records, the source of all existence and knowledge. This granted him omniscience—understanding past, present, and future—alongside potent psychic abilities. Though powerful, he remained human, enduring a curse of longevity that forced him to repeatedly outlive his students across centuries.

His omniscience revealed his destined role opposing the mage Animus and the Biscuit Hammer. He foresaw his final apprentices would be the Turtle Knight Yukimachi Tsukishiro and the Rooster Knight Subaru Hoshikawa, whom he mentored years before the Beast Knights assembled. He trained them in combat and psychic techniques; inheriting his abilities, Yukimachi and Subaru developed complementary defenses, an "unbreakable shield" and "unstoppable spear" when combining their Holding Fields.

Akitani's powers included teleportation, spatial manipulation (swapping object locations), telekinesis, energy projection, and forcefield creation via Domain Control. His precognition provided limited future insights, ceasing after death. Despite advanced age and waning strength, he executed the potent Heavenly Jewelled Spear psychic attack, capable of injuring a six-eyed golem. He also possessed a single-use wish-granting ability, restricted from defeating Animus or resurrecting the dead.

He died sacrificing himself to protect Yukimachi and Subaru from a golem attack, fulfilling his vision of perishing before his students. Before his death, he buried a journal for the Lizard Knight, Yuuhi Amamiya. It contained his life story and fragmented visions of the future. The journal omitted details about most Beast Knights but explicitly addressed Yuuhi, implying a challenge for him to confront Samidare Asahina's destructive intentions. Akitani's legacy persisted through Yukimachi and Subaru, whose combined strength reflected his teachings.