Mitsuri Kanroji was exhausted. She went to the blacksmiths' village because she needed a new sword and also some rest. Killing demons is exhausting work regardless of your rank as a demon slayer. There she relaxed in the hot springs, talked to a boy but he ignored her, she met Tanjiro and Nezuko Kamado and had dinner with them, having a good time.

It was a quiet night, she didn't have to worry about anything else, or so she thought, because Tanjiro, Muichiro, who was also in the village, and Nazuko were attacked by none other than Upper Moon Four, Hantengu. However, she only joined the fight when the four clones merged into one; Zohakuten, clone of hatred and the final form. Until then, the ones who had been fighting were Tanjiro, Nezuko, and Genya, whose name she knew because Tanjiro had told her during dinner. She arrived just in time to rescue Tanjiro, who had been swallowed by one of Zohakuten's wooden dragons.

She was reckless at first and, without knowing it, tried to decapitate the demon, but it attacked her and almost killed her. Tanjiro, Nezuko, and Genya saved her. She reacted and fought Zohakuten, even preventing him from going after the other three who were chasing Hangentu's main body. "I'm not letting you go that way!" she said, and used her sword to cut down the wooden dragons.

Mitsuri fought for 1-2 hours, which was exhausting. She unlocked the demon slayer's mark and was even stronger, faster, but fighting an Upper Moon is not that easy, which is why the Hashira rank is not so easy to obtain. Anyway, she was out of alignment, her body ached from exhaustion, and she was lucky to still be standing. At one point, she simply couldn't take it anymore; by that point, she was dodging attacks instead of fighting.

She struck one of the wooden dragons with her sword. "I can't take it any more"’ she cried, frustrated. "I'm so sorry!" Tears clouded her vision. "I'm about to be killed!" were her last words, and the dragon swallowed her. Everything went black... but it wasn't more than five seconds before someone else cut the dragon and she was suddenly freed, kneeling on the ground. She looked up to find someone standing in front of her, protecting her. Another demon slayer has come to fight. Luck was on her side.