TV-Series
Description
Yahiko is a fox yōkai who shifts between human and animal forms. His fox guise features white fur with black ears and front paws, a large three-split fluffy tail, and a yellow cloud-patterned scarf. As a human, he resembles a twelve-year-old boy with light brown hair, typically dressed in a white and reddish-brown kimono with sandals. His eyes narrow and shift to red when angered or serious.

Mischievous and playful, he often displays childlike behavior, enjoying games like hide-and-seek, snacks such as rakugan, and being brushed by Zenko. His long lifespan grants him a distinct perception of time. He fears relationship changes, expressing palpable relief upon reuniting with Haruitsuki Abeno after hearing troubling rumors. Though disliking Hanae Ashiya, he maintains cordial interactions.

Yahiko wields extensive transformation powers, shifting into animals, humans, inanimate objects like gravestones, or mimicking others' appearances such as Haruitsuki. He flies in fox form and creates seals by biting people. While emitting a threatening aura, he can conceal it entirely, evading even seasoned exorcists.

His history includes an eight-year bond with Abeno, forged when a seven-year-old Abeno became lost in a forest; they played hide-and-seek for three days. Rumors later sparked Yahiko's worry over Abeno's unchanging nature. After reuniting, Yahiko bit Zenko Fujiwara to force Abeno and Ashiya into hide-and-seek, resulting in a year-long punishment assisting at Zenko's temple. He relishes lounging there and being groomed by Zenko.

He develops a close friendship with Kinako, a yōkai he initially frightened in a forest. They frequently play hide-and-seek and tag, though Kinako fails to recognize his human form. When Kinako struggles to maintain her transformed state, Yahiko grows concerned for her well-being and insists Abeno exorcise her. He shares a final play session before her exorcism, accepting their separation with sadness.

A significant revelation identifies him as the elder brother of the underworld princess, tying him to the underworld's royal lineage. However, he cannot enter the underworld himself. His ongoing role at Zenko's temple and interactions with the main characters highlight his loyalty and gradual maturity while preserving his playful essence.