Susamaru, along with Yahaba, was one of the main antagonists of the Asakusa Arc. She was a demon that aspired to join Muzan Kibutsuji's Twelve Kizuki. Susamaru was a pale-skinned woman with bright yellow eyes with cat-like slits and white horizontal slats with black hair with orange-colored ends. She was taller than Tanjiro. Her hair was styled as bangs at the front. Susamaru wore a pair of long silver earrings and an orange kimono that matched her hair. She had a black haori on top but took them both off when she entered her battle, revealing a small black sarashi that covers her chest and upper abdomen. Although she normally had an average build, when fighting seriously, her body became noticeably more muscular. She could also grow two new pairs of arms as well. Susamaru was shown to be rather playful, yet very brash and quite immature while almost always smiling and always enjoys and accepts a challenge. Her pet phrase is "what fun this is" and she will repeat this constantly if engaged in bouts she deems amusing. Her immaturity is a stark contrast to Yahaba's seriousness. She was fanatically loyal to Muzan and battled to her best ability in the hope of killing Tanjiro and taking Tamayo hostage for her master. When the latter had denounced Muzan as a manipulative coward, she defended his honour and denied her statements vehemently. In her final moments, it is revealed that Susamaru was really just a girl pushed by the Demon Progenitor with the false notion of being a Twelve Kizuki, and her act of calling out to Tanjiro to play with her last temari caused him to lament her manipulation and blind devotion just to die brutally in the end.