Susamaru is a demon characterized by pale skin and bright yellow eyes with cat-like slits. Her black hair features orange-colored ends and front bangs. She adorns herself with long silver earrings and typically wears an orange kimono covered by a black haori, which she discards in combat to reveal a black sarashi binding her chest and upper abdomen. Her physique appears average at rest but becomes visibly muscular during intense fights; she can also grow two additional pairs of arms, totaling six limbs. Her personality is playful and brash, marked by immaturity and a near-constant smile in battle. She frequently exclaims "what fun this is" during engagements she finds entertaining, a stark contrast to her partner Yahaba's seriousness. Susamaru displays fanatical loyalty to Muzan Kibutsuji, vehemently defending his honor and striving to kill targets like Tanjiro Kamado to gain his favor. This devotion stems from Muzan's manipulation: he transformed her from a young girl who enjoyed temari handballs into a demon, falsely convincing her she was a member of the Twelve Kizuki. Summoned alongside Yahaba by Muzan in the Asakusa Arc to hunt Tanjiro, Susamaru utilizes Yahaba's Blood Demon Art for tracking. She destroys Tamayo's hidden residence with her temari balls. In the ensuing battle, she decapitates Yushiro and severs Nezuko Kamado's leg, growing additional arms to wield six temari simultaneously. She coordinates her attacks with Yahaba's directional arrows for increased lethality. When Nezuko deflects her temari kicks, Susamaru intensifies her assault until interrupted by Tamayo. Tamayo employs her Blood Demon Art to lower Susamaru's mental defenses, tricking her into speaking Muzan's full name. This activates Muzan's curse, manifesting as three demonic arms that crush her body, leaving only fragments. Tamayo observes the absence of a Twelve Kizuki rank number in her eye, confirming her non-member status. In her final moments, a disembodied voice requests a temari; Tanjiro returns it. Her remains dissipate at sunrise. Her primary ability is the Blood Demon Art Hiasobi Temari, conjuring dense temari balls. She throws or kicks them at high speeds with sufficient force to decapitate enemies, sever limbs, or demolish structures. She possesses common demonic attributes: enhanced strength, rapid regeneration (demonstrated by regrowing severed arms), and flesh manipulation for limb multiplication. Her combat effectiveness increases significantly when Yahaba's arrows guide her temari trajectories. Her narrative concludes within the Asakusa Arc.