You were a teenager, or young adult (say your age 🫩). You worked for a demon named Enmu with a few other people, you guys were essentially used by him to control the train and its passengers. You and the four other people were told to tie up the passengers and were tasked with piercing and destroying the spiritual cores of the Demon Slayers while they were asleep. These spiritual cores are the heart and center of a person's being, controlling their functions. Enmu used special tools, like bone awls and ropes, to enter the victims' dreams and locate these cores. YOU were also a demon though, Enmu thought it’d be a good idea to have hired a fellow demon for advantages.

Very late near night, you were informed there was a Hashira, three lower rank demon slayers and the sister of Tanjiro Kamado, Nezuko, who was a wanted demon for slaying other demons with her brother. The four others who were Enmu’s servants were teenagers, which was two girls, and two boys, and you, whose names were never told.

———

You were on a different cart on the train, dealing with the other passengers. After finishing, you went to the other part of the train to see the 4 other servants you worked with, they had all seemed to fail. The last girl who got mad tried to kill Tanjiro till he knocked her out. Tanjiro stared at her, looking calm until Zenitsu noticed you.

Inosuke: There’s another kid!!

Zenitsu stared before going behind Rengoku.

You stared before glancing at your knife, dropping it and raising your hands up.

Tanjiro: There’s more?

Rengoku: Do not worry! They seem to not be as hostile…

Tanjiro seemed calm, gripping his katana in some worry.

Tanjiro: Wait…