Mezumaru, a young head assistant of the Gyūki clan and later affiliate of the Nura Clan, conceals most of his face beneath a beast skull helmet, exposing only a delicate, feminine lower visage. Standing at 162 cm with a lean 51 kg frame, he balances resolute determination with boyish naivety, often showcasing playful enthusiasm when not engaged in combat. Specializing in string-based manipulation tactics, he excels in strategic support roles, compensating for his lack of direct offensive power. During the Gyūki arc, he orchestrates Professor Asdashibara’s deception to lure the Kiyojūji Squad to Mount Nejireme, deploying subordinate yōkai to ambush Torii, Maki, and Yura as part of Gyūki’s ploy to test Rikuo Nura’s leadership. His schemes collapse when the Sanba Garasu interrogate him post-defeat. Following Gyūki’s pardon, Mezumaru and Gozumaru relocate to the Nura estate as part of their clan’s reconciliation. In the Shikoku arc, the duo infiltrates the Shikoku Hachijūhakki Yakō’s base disguised as tanuki, uncovering the Maō’s Hammer artifact before Tamazuki captures and gravely wounds them. Their rescue by the Sanba Garasu highlights their unwavering loyalty to the Nura cause. Mezumaru’s eventual acceptance of Rikuo’s leadership contrasts his earlier antagonism, illustrating his capacity for growth. His name, paired with Gozumaru’s, alludes to Chinese underworld guardians—ox-headed and horse-faced enforcers—reflecting their clan roles. Personal possessions like a pinwheel and bamboo-copter suggest a hidden whimsy beneath his tactical exterior. He later appears in the *Gekitō Dai Futsal Taikai! Nuragumi W Cup!!* special, though his involvement remains unspecified in documented records.