Kyosuke Shigure is a reserved, eloquent individual defined by humility and a powerful sense of honor. His near-perfect articulation reflects his disciplined nature. Raised solely by his older sister in a small village following his parents' early divorce, he witnessed her sacrifice as she supported them through university studies and part-time work; Kyosuke also worked to lessen her burden. When his sister introduced a man named Osaki, Kyosuke distrusted him. Osaki, sensing Kyosuke's latent power, manipulated his sister into marriage and later murdered her to forcibly awaken Kyosuke's abilities. This tragedy shattered Kyosuke emotionally, leaving him describing himself as "half-dead," and ignited his lifelong quest for vengeance.

He wields a spiritually attuned wooden practice sword, the Youto Kagura bokken. Despite lacking a Kaizer Stone, he possesses formidable combat skills and spiritual abilities. His powers include summoning three animal spirits: the wolf Kubira, which mauls and electrocutes foes; the hawk Basara, which attacks with fireballs; and the monkey Mokora for direct assaults. A fourth spirit, Gaia, manifests as a muscular humanoid to damage nearby enemies. Kyosuke can also manipulate his shadow as a whip-like weapon using his sword. Kubira, his canine spirit, can shapeshift into human form and serves as a loyal companion during his mission.

Pursuing revenge, Kyosuke infiltrates the Bernard Institute in Neo Tokyo, where Osaki serves as principal. He maintains a low profile, avoiding unnecessary interactions yet remaining courteous. His tactical approach is methodical, prioritizing intelligence gathering over impulsive action. During the final confrontation, he faces Ohga, the mastermind behind Osaki. In the game's ending, he remains inside an exploding facility, implied to have chosen death, with allies Kash, Isato, and Ikki observing from afar. Conversely, the OVA adaptation depicts him surviving the explosion after rescuing a classmate, Suzu Asahina, indicating a divergence in his fate across media.

Beyond his vendetta, Kyosuke dislikes summer due to cultural associations with heightened supernatural activity and prefers winter when such forces recede. His familiars—Kubira, Basara, and Mokora—draw direct inspiration from the protectors in the Japanese folktale Momotaro, underscoring his role as a supernatural-themed fighter.