TV-Series
Description
Wanyûdo serves as Enma Ai's companion across all official series installments. His existence began over 400 years ago as the left wheel of a royal carriage. During a wartime escape attempt, the carriage carrying a princess and attendants was struck by fire arrows and plunged off a cliff. All perished, and the wheel, infused with lingering anguish, manifested as a youkai—a flaming wheel with a human face at its hubcap. This form haunted travelers near the cliff nightly until Enma Ai intervened, offering him a place at her side. She granted him a human form, marking him as her first companion.

In human guise, Wanyûdo appears as an elderly man with narrowly opened eyes, typically dressed in traditional Japanese attire: a haori, yukata, straw zōri, and a light gray fedora. He often wears a red scarf around his neck, though this becomes less frequent in later seasons. His clothing evolves slightly, shifting from dark red-brown and khaki garments to a brown haori over a dark gray yukata with a purple nagajuban underneath. For duties, he reverts to core forms: a black straw doll with a red string around its neck, a flaming wheel with his visage at the hub, or a full black-and-red carriage bearing Hell's contract crest. The carriage form levitates autonomously, lacking draft animals.

Generally calm and mild-mannered, Wanyûdo shows reluctance toward aggression and maintains composure in tense situations. He possesses extensive knowledge of supernatural phenomena, often deducing events before other companions. Despite his reserved nature, he occasionally engages in light humor and habitually smokes. Loyalty to Ai defines his actions, though he harbors a consistent dislike for Kikuri. Beneath his aged exterior lies formidable martial prowess and superhuman strength, demonstrated when he halted a truck from tumbling off a cliff.

His abilities include multifaceted transformations into straw doll, wheel, or carriage forms; magically altering clothing for investigations; and manipulating memories to implant false identities or familiarity in humans. He travels freely between the human world and the Realm of Eternal Twilight. Fire manipulation is intrinsic to his nature, allowing projectiles in human form and environmental ignition in wheel form. Possessing a wheel or vehicle grants him control over machinery like turbines or automobiles. He also levitates, flies in non-human forms, and resists magical assaults.

Following Ai's self-sacrifice at the end of the second season, Wanyûdo lived briefly as a human construction worker. Kikuri later recruited him back into service upon Ai's return. During the third season, he worked undercover as a school janitor in Saigawara City. When Yuzuki Mikage temporarily became Hell Girl, Wanyûdo aided her independently—unlike other companions—before returning to Ai after she resumed her duties. His presence continues through the fourth season, maintaining his role within Ai's operations.