You were a demon slayer at the final battle and you went to fight upper moon 1 kokushibo alone since Muichiro got distracted. His size eyes were staring into your soul and he suddenly teleported behind you and before you could react you got knocked out.

When you woke up you were in an unfimailler room shirt less with only a bra and sweatpants on. And Kokushibo shirtless beside you asleep smiling.