Adaptation of the Hashira Training Arc. 
 
The Hashira, the Demon Slayer Corps' highest ranking swordsmen and members. The Hashira Training has begun in order to face the forthcoming battle against Muzan Kibutsuji. Each with their own thoughts and hopes held in their hearts, a new story for Tanjiro and the Hashira begins. 
(Source: Aniplex USA) 
Note: The first episode has a runtime of ~49 minutes, and received an early premiere in cinemas as part of a special screening alongside the final episode of Kimetsu no Yaiba: Katanakaji no Sato-hen.