Kimetsu no Yaiba Wiki
Kimetsu no Yaiba Wiki

Kotetsu ( () (てつ) さん Kotetsu-san?) is the one hundred and fourth chapter of Koyoharu Gotoge's Kimetsu no Yaiba.


Kotetsu proposes a variety of insults Tanjiro could use once he becomes stronger than Muichiro, but Tanjiro refuses the thought and tells himself he has to become stronger. He begins to train with Yoriichi Type Zero, with Kotetsu’s analytical skills and newfound motivation being used to excessively critique the Demon Slayer’s movements. He declares that until Tanjiro can accomplish what he wants, he won’t receive food.

Kotetsu adjusts the doll by twisting its fingers.

Kotetsu shows Tanjiro another method of adjusting the doll’s movements through twisting its fingers—such that it’d coordinate with its users’ weaknesses—and compares the actions to that of playing with a wooden puzzle box. After readjusting the doll, Tanjiro continues brutally training with it without food, water, or sleep under Kotetsu’s direction, because the latter does not understand the limits of a human.

Just as Tanjiro approaches the brink of death, analogous to nearly crossing the Sanzu River, he becomes capable of smelling the incoming movement of the doll and lands a hit on it, earning him his first meal. After gaining this ability to predict movements, Tanjiro continues to train it and improves his stamina and foresight.

A sword's hilt emerges from Yoriichi Type Zero.

In the middle of a spar with the doll, Tanjiro’s newly improved abilities grant him an opening to behead it, however, he hesitates mid-swing and worries about breaking the doll. Kotetsu yells at him to strike, reassuring him that he would be able to fix it. Internally, the young boy begs Tanjiro to not waver so that one day, he will become stronger than anyone else.

With Kotetsu's approval obtained, Tanjiro succeeds in landing a blow to the doll’s neck and breaks his training sword in the process. He apologizes to Kotetsu for the ruined sword and, after Kotetsu's sudden exclamation, Tanjiro turns to see a sword’s hilt emerging from the doll’s body where its head used to be.

Characters in Order of Appearance


  • Tanjiro begins training with Yoriichi Type Zero under Kotetsu's instruction.
  • Tanjiro succeeds in landing a blow on the doll's neck, revealing a sword's hilt.