Swamp Demon

Once human, the Swamp Demon has pale skin, long blue hair, and a pair of violet strands by his face kept apart with golden clips. His nails are claw-like, the veins on his forehead replace his eyebrows, and his pupilless red eyes sit above heavy dark shadows.

Because he can split into three separate bodies, each version differs in horn count and clothing. The main body has a single central horn and a long-sleeved ninja garment lined with mesh. The second has a horn on each side and a sleeveless outfit, while the third bears three horns and a coat stitched with mesh across the arms, shoulders, and torso.

Splitting into three also divides his temperament. The main self is calm, analytical, and serene, acting as the group's leader and even urging the others to settle down. He shows a coldly logical streak, questioning Tanjiro's bond with the demon Nezuko, and a sociopathic side in targeting a specific type of victim and hoarding their hair ornaments as trophies.

The second body is impulsive, violent, and quick to anger, voicing the emotions the main self conceals. The third acts almost purely on instinct, wordless and dog-like as it follows the others. All three share a craving to devour young women and a paralyzing terror of Muzan, whose name alone makes their bodies tremble.

The Swamp Demon once crossed paths with his creator, Muzan Kibutsuji. After a brutal beating, he was ordered never to reveal Muzan's name and warned that he would always be watched. The encounter left him so frightened that he obeyed the command absolutely.

During Tanjiro's first mission, the demon preys on a town where girls vanish each night. Tanjiro tracks him by scent, rescues a captive, and clashes with all three bodies at once, aided by Nezuko. Using Water Breathing forms suited to the swamp, Tanjiro slays the clones inside the pocket dimension while Nezuko overwhelms the last self with her fists. After cornering the survivor and pressing for information about Muzan, Tanjiro finds the demon too consumed by fear to speak, and finishes him off, avenging the many victims (Chapter 13).