Hashira Training

The Hashira Training is a series of special training session instructed by the Hashira. It takes place before Muzan Kibutsuji's first direct confrontation with the Demon Slayer Corps.

History
After the events in the Swordsmith Village, Amane Ubuyashiki held an emergency Hashira Meeting. She informs the Hashira that since Nezuko Kamado is able to conquer the sun, Muzan will go after her and the time for an all-out battle against him and the demons is approaching soon. Since Demon Slayer Marks started appearing after Tanjiro Kamado unlocked it first, she requests the Hashira to train in order for all of them to unlock their marks and that any Demon Slayers with marks regardless of their status must participate. The Hashira's agree and Gyomei Himejima has a proposition on how to tackle this.

Because of their busy schedule which includes protecting their assigned regions, gathering information on demons and improving their swordsmanship, Hashira did not having time to train anyone other than their successors, the Tsuguko. But since Nezuko conquered the sun, the demons stopped appearing and Hashira only focus on night patrol and day training now.

Hashira Training Sessions
The training consists of sessions of lower-ranking Demon Slayers training with each of the Hashira:

The Hashira themselves improve by facing waves upon waves of swordsmen. If anyone's heart rate and temperature is high enough for the mark to appear, then everyone wins. Those who already have marks will train to continuously stay in the marked state.