Kimetsu no Yaiba Wiki
Kimetsu no Yaiba Wiki

Robust Blade (強靱な刃 Kyōjin'na Yaiba?) is the fourth volume of Kimetsu no Yaiba.



After a fierce battle with a demon inside a maddening house of ever-changing rooms, Tanjiro has a chance to find out about the fighter in the boar-head mask. Who is this passionate swordsman and what does he want? Later, a new mission has Tanjiro and his compatriots heading for Mt. Natagumo and a confrontation with a mysterious and horrifying threat...[6]

Author's Comment

I did it! I'm Gotouge. I got comments from Togashi Sensei on the obi! It's like a dream! My stomach hurts! Thank you very much to Togashi Sensei, everyone rooting for me, and everyone who helps out. I'll work as hard as I can!

Koyoharu Gotōge, Volume 4

Extra Pages

Image Context


  • Inosuke - Showing off his flexibility and Jiujitsu
  • Shinobu and Giyu - Shinobu continuously tries to speak to Giyu to befriend him, but he remains indifferent.
  • Zenitsu - Zenitsu frantically calls out to Nezuko to try to find her.
  • Zenitsu 2 - Zenitsu becomes lost in the forest and is alone. He calls out to his sparrow, Tanjiro, and Inosuke.
  • Koyoharu and Older Brother Spider Demon - Koyoharu covers their nose as they smell the Older Brother Spider Demon's odor
  • Zenitsu 3 - Zenitsu is seen kneeling with 3 large welts on his head.

Taisho Secrets

  1. Shoichi, Teruko, and Kiyoshi voice out their fatigue while the author ushers them to take care of themselves and have a good rest.

Comic Strips

Steel Head

Tanjiro demonstrates a number of uses for his steel forehead, such as headbutting an opponent, splitting wood and acting as a portable cutting board. Zenitsu cant believe this and says that Tanjiro wont fool him.

Gender Bending

A series of gender bent versions of the main cast of characters and their names

  • Inosuke - Inoko
  • Nezuko - Nezuo
  • Zenitsu - Yoshiko
  • Tanjiro - Sumiko


The author apologizes for revealing Inosuke's face in the gender bending comic strip which premiered in Jump GIGA before it was officially unveiled in the main series. They as well as tanjiro and Nezuko bow their heads whilst asking for this forgiveness

Kimetsu Academy Tales

  1. Inosuke - a student who was raised by wild boars, and is currently living with his foster parent; He is a known topic on TV and in places. He only eats bentos at school, and refuses to wear any shoes. He wears his short sleeve uniform all year around.
    • Hisa - Inosuke's foster parent; Her special dish is tempura, and when things turn bad she pretends to have bad hearing.
2. Swamp Demon - A weirdo who appeared in the town of Kimetsu; He homes in on 16 years old girls. He has become an urban legend because he is often witnessed at multiple incidents which occur at the same time. However, Tanjiro has deducted that he is not a triplet and is currently pursuing this case.

Words of Gratitude

The author thanks the reader for rooting for them, as well as everyone who helps them out. They say they are so happy about the letters and presents they have received that it makes them cry. They promise to keep working as hard as they can