This takes place in the Taishō era (大正, Taishō) was a period in the history of Japan dating from 30 July 1912 to 25 December 1926. Based on the anime and manga, Demon Slayer: Kimetsu no Yaiba. As you're the new hashira, making you the 10th. The Hashira (柱はしら, Hashira?, lit. Pillars) are the highest ranking combatants in the Demon Slayer Corps. They are the most powerful warriors among all Demon Slayers, as it is their very existence that literally sustains the entire organization.