Susamaru is a pale-skinned woman with bright hazel eyes with cat-like slits and white horizontal slats with black hair with orange-colored ends. She has bangs over her forehead and the ends of her hair appear similar to paintbrushes.
Susamaru wears a pair of long silver earrings and an orange kimono that matches her hair. She wears a black haori on top but takes them both off when she enters battle, revealing a small black sarashi that covers her chest and upper abdomen.
Although she normally has an average build, when fighting seriously, her body becomes noticeably more muscular. She can also grow two new pairs of arms as well.
Susamaru is 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.
Susamaru was a young girl who enjoyed playing handball before she was taken over by Muzan. He implanted her with the desire to become one of the Twelve Kizuki while killing his enemies using her handballs.
Due to Muzan's guidance down this dark path, Susamaru is a carefree demon who desires to please her master while enjoying herself at the same time.
Outraged by the appearance of a Demon Slayer wearing hanafuda-like earrings in Asakusa, Muzan Kibutsuji summons two of his followers to hunt him down. Susamaru and Yahaba walk the streets of the busy city searching for a trail to their next target. Yahaba uses his Blood Demon Art to track the footsteps of a Demon Slayer carrying a large box. Susamaru walks alongside him, bouncing her temari ball as she follows along.
Yahaba finds that the Demon Slayer is being accompanied by others. Excited to slaughter them all, Susamaru asks how they should go about destroying them. Yahaba replies that of course, they must execute them vindictively for Lord Kibutsuji, much to Susamaru's liking. Susamaru follows her partner to an invisible house hidden behind a fake wall.
Susamaru uses her temari to destroy the seal hiding the building. Having tracked down their enemy, Susamaru agrees with Yahaba that they must kill them all brutally. Using Yahaba's arrows to guide her mari balls, Susamaru tears apart the house piece by piece. Her temari tear through the walls, floor, and roof of the house. After making a large enough opening to see inside the house, Susamaru notices the Demon Slayer with hanafuda-like earrings inside.
Yahaba scolds Susamaru for her immature approach and for splattering dust on his kimono. Susamaru ignores him and continues having fun, replying only that Yahaba needs to relax and let loose on the enemy. Yahaba falls back and uses his arrows to guide Susamaru's temari at the enemy. The Temari Demon manages to take off Yushiro's head with a single ball.
Susamaru tells the Demon Slayer that its time to die and darts a mari ball straight for him. He counters by stabbing the ball at an angle, impressing Susamaru. Yushiro's head regenerates and he curses the Temari Demon for ruining his peace with Lady Tamayo. Susamaru claims he's babbling and removes her kimono to grow four more arms. She tells them all that they should be honored to be killed by one of the Twelve Kizuki.
The Temari Demon prepares six mari balls and asks her opponents to keep playing until they die. She tears up the house and injures the two Demons. Yushiro gives Tanjiro a way to see Yahaba's arrows and then he is effectively able to counter the temari. Susamaru returns her balls and Tanjiro confronts her directly. She tells him that she's going to bring Lord Kibutsuji his head for sure. Meanwhile, Tanjiro's sister Nezuko attacks Yahaba and dispells his arrows.
Without the guidance of Yahaba's arrows, Susamaru's balls are left open to counterattack and sliced to pieces by the Demon Slayer. Tanjiro uses a flowing dance technique and even manages to slice off all the Temari Demon's arms at once. He swears to Tamayo to extract blood from Demons close to Muzan.
Amused, Susamaru asks Tanjiro what he is scheming to do with their blood. She refuses to allow him to displease Lord Kibutsuji and challenges him to take on the Twelve Kizuki. She instantly regenerates all six of her arms back and reminds Tanjiro that she'll be taking his head. Yahaba returns to the battlefield and throws Nezuko into her brother. Susamaru tries to kill them both at the same time but they're able to avoid it. Tanjiro takes on Yahaba while the other three deal with the Temari Demon.
Yushiro turns invisible using his Blood Demon Art and brings Susamaru to her knees while telling her to repent for hurting Lady Tamayo. Yahaba recognizes Tamayo's name as Tamayo the fugitive and Susamaru agrees she'll make a good souvenir. Susamaru goes back on the offensive and severs Nezuko's leg before kicking her back into the house. She asks if four heads will be enough for Kibutsuji but Yahaba claims they're only taking Tanjiro and Tamayo's.
Susamaru kicks up a lot of dust by bouncing six of her balls, creating a smokescreen. Yushiro is able to evade the temari despite the dust and tries to close in on his enemy. The Temari Demon can see him moving through the dust despite his invisibility and throws another ball straight for his head. He's nearly decapitated again but a healed Nezuko arrives in time to kick the ball away.
The Temari Demon keeps up her attack, but this time Nezuko is able to deflect the balls with kicks. Annoyed, Susamaru calls Nezuko a brat and challenges her. They kick the temari back and forth at incredible speeds where Nezuko proves she's growing in strength by the second. Nezuko is even able to kick the ball back so fast and hard that Susamaru can't even return it.
Impressed, Susamaru decides to go all out against Nezuko but Tamayo interrupts. She asks Susamaru about Muzan, calling him a coward for playing Demons against each other and manipulating them. Enraged, Susamaru tries to defend her master's honor but accidentally says his name out loud. Her brain function was inhibited by Tamayo's enchanting blood, which she secretly cast across the area, forcing Susamaru to tell the truth.
Horrified, Susamaru runs away and begs for forgiveness from her lord. However, having invoked his name out loud, Kibutsuji's curse takes hold of Susamaru and three demonic arms spawn from her body. The arms crush Susamaru's body completely, leaving only her eye, an arm, and a pool of blood. Tamayo notices her eye isn't marked with a number, meaning she's not actually one of the Twelve Kizuki.
Tamayo takes a sample of Susamaru's blood and Tanjiro notices a faint voice asking for a mari ball. Tanjiro returns her mari and laments how Muzan manipulated Susamaru into thinking she was one of the Twelve Kizuki and compelled to fight until her eventual death. The sun rises and the remains of her arm is completely disintegrated.
Overall Abilities: Susamaru was a decently powerful demon, as evidenced by possessing a Blood Demon Art and displaying a proficiency in utilizing in combat. Most notably, she possesses incredible physical strength which allows her to throw and kick her Temari handballs at extreme speeds and with tremendous strength. It is particularly efficient when used in conjunction with Yahaba's Koketsu arrows. Together, they were able to flush Tamayo out of hiding and destroy their hideout.
Flesh Manipulation: Like all demons, Susamaru possesses the ability to control and alter her flesh to a certain extent. Susamaru briefly uses this ability to grow 4 more arms, allowing her to conjure more handballs, increasing her offensive output.
Hiasobi Temari (
Game Exclusive Techniques
- Play Ball (
毬 遊び Mariasobi?): Susamaru kicks a spinning kemari that whiffs towards her opponent and hits them in the abdomen.
- Spinning Throw (
転 身 打ち Tenshin Uchi?): Susamaru leaps to the side, dodging the majority of attacks and hurls a powerful temari towards her opponent.
- Piercing Kick (
貫き 蹴り Tsuranuki Keri?): Susamaru quickly sprints towards her opponent, using the momentum to unleash a powerful kick.
- Sixfold Temari (
陸 連 毬Rokurenmari?): Susamaru casts a barrage of 6 temari towards her opponent before unleashing a final and powerful temari.
- Spiraling Shot (
螺 旋 蹴 毬Rasen Kemari?): Susamaru throws a barrage of temari towards her opponent, completely pulverizing them. During this she creates a kemari using all six of her arms and spins it, greatly increasing its potential and kinetic energy, to which she kicks it towards her opponent causing them to soar in the air followed by a huge explosion of blood.
- Susamaru was ranked in 30th place as of the first character popularity poll with 53 votes.
- In Kimetsu Academy, Susamaru is a third year from the Mogura class and president of the volleyball team. Her full name is "Maru Susa."