Yashichi is a Muglox fairy partnered with Azumi Hidaka. Brash and impatient, he frequently appears alongside his henchmen, Sasuke and Hanzo. His primary role involves antagonizing his long-time rival, Mirumo, though they collaborate when necessary to protect their partners or face greater threats. Physically resembling a ninja, Yashichi wields a triangle as his magical instrument. He possesses a fascination for collecting and sketching underwear, a habit that frequently embarrasses Azumi. Initially loyal to the Warumo Gang, he abandons them when their actions endanger Azumi, revealing his deeper commitment to her.

His relationship with Azumi is contentious; she often assigns him household chores like a servant and reacts violently to his antics. Yet he acknowledges their mutual dependence, and his allegiance to her strengthens over time. During the Golden season, he initially obeys a Warumo Gang order to attack humans but defects when Azumi is harmed, defending her and aiding Mirumo to defeat the gang. This act solidifies their bond, prompting Azumi to show emotional appreciation. Yashichi's development includes a near-sacrifice where he attempts forbidden magic to grant Azumi a wish, risking permanent petrification. Moved by his selflessness, Azumi uses her wish to restore him. In later seasons, he assists in crystal collection efforts and supports Azumi's romantic schemes, often employing mischief or magical interference.

Key aspects include his favorite food, karinto, and his role mentoring Sasuke and Hanzo. His dynamic with Mirumo evolves from pure rivalry to a grudging partnership during critical missions.