Hashira Training

The Hashira Training is a training program held at the Demon Slayer Corps Headquarters. It was conducted by the Hashira and undertaken by numerous lower-ranked Demon Slayers. The training took place before the final battle.

Overview
The goals of the training program are twofold:
 * 1) To improve all Demon Slayers' physical abilities and overall health, bolstering the members of the Demon Slayer Corps significantly.
 * 2) To improve the individual strength of each Hashira as well as practice coordinating their attacks together.

This training method has proven to be very effective in the final battle where the majority of Demon Slayers were able to effectively kill Lower Rank-level demons regardless of their ranking.

Training program
Each of the Hashira oversees a different component of the training program for lower-ranking Demon Slayers, which includes basic stamina training, flexibility training, quick movement training, sword skill training, pounding training, and muscle reinforcement training.

The training sessions are extremely strenuous; because of this, a majority of the Demon Slayers view the training session as an everlasting trip in hell, with a few notable exceptions who see the session as a chance to improve themselves.

The components of the program include sessions with each Hashira on their respective training ground in the following order:

As a general rule, Hashira must take part in each other's training sessions. It is considered a win-win situation for both the Hashira and the Demon Slayers, as even the Hashira get to improve due to constantly facing waves upon waves of junior swordsmen ranked lower than themselves. This accelerates their heart rate and temperature, which might help with unlocking the Demon Slayer Mark. Those who already have marks will train to continuously stay in the marked state.

Other than the sessions with the lower-ranked Demon Slayers, the Hashira also battle one on one using their own Breathing Styles with wooden swords. The purpose is to coordinate their attacks while using two different kind of breathing styles, so they won't interfere each other's attacks during a future battle that is moving at a high pace.

Shinobu Kocho, the Insect Hashira, was the only Hashira who did not participate in any training sessions due to the significant amount of time she needed to prepare poison for the Final Battle. After the Hashira meeting, she informed Gyomei of this choice, who accepted this.

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 his first, she requests the Hashira to train themselves to unlock their marks and that any Demon Slayers with marks regardless of their status must participate. The Hashira agree. Gyomei Himejima then announces to the other Hashira that he has a proposition on how to tackle this. Sharing the idea of a training program, he requested every Hashira to set the contents of their training and get their preparations done for it.

Because of their busy schedule which includes protecting their assigned regions, gathering information on demons and improving their swordsmanship, Hashira normally 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 have to focus on night patrol and day training now. The extra free time allows them to train lower-ranking Demon Slayers as well.