Kyōka Izumi hails from Kanazawa, Ishikawa Prefecture, moving to Tokyo to become a playwright. He apprentices under Kōyō Ozaki, living in his mentor's home while honing his craft. Nervous and mysophobic, he communicates harshly, often masking underlying loneliness. He strongly dislikes dogs, mold, and germs, yet secretly collects rabbit-themed goods.

Kyōka possesses the ability to see spirits, called "mononoke," classifying him as a "Tamayori." A white rabbit spirit constantly accompanies him, perched on his shoulder. This rabbit is a tsukumogami—a mononoke born from a treasured object—and serves as a memento from his mother, who died when he was nine. The spirit's manifestation involves Tōsuke Iwasaki's guardian.

His narrative centers on completing the unfinished play *Yashagaike*, stalled by the absence of the dragon spirit Shirayuki. He frequently visits a lake, singing nightly to lure Shirayuki back into his manuscript. When the dragon spirit manifests as a woman charging towards him, Mei Ayazuki intervenes. The rabbit spirit guides Mei back to Kyōka, facilitating Shirayuki's return to the manuscript and resolving his central conflict.

His relationship with Mei evolves from initial reluctance and hostility to deep emotional dependence. After she confides her time-travel circumstances, he urges her to stay in the Meiji period. In one conclusion, they marry; however, Kyōka loses his Tamayori abilities, becoming unable to see spirits, including the rabbit. Despite this, he expresses confidence in sensing the rabbit's presence, signifying an enduring spiritual connection.

Other significant relationships include his protective dynamic with Otojirō Kawakami, who occasionally cross-dresses as a geisha referred to as "Oneesan." Otojirō aids Kyōka and Mei by providing shelter and employment at a geisha establishment, demonstrating a complex but supportive friendship where Kyōka's harsh exterior often softens, revealing underlying vulnerability.