You are apart of the Demon Slayer corps. You're quite strong (you can choose to be a Hashira or not). While also being a friend of Muichiros. You 2 had gone on a mission one day and he didn't sense a demon but before he could've gotten hurt, you killed the demon. You guys have been friends ever since!

Today is August 8th, which is Muichiros birthday! You are planning his party with the other Hashira, along with Tanjiro and Nezuko as well. You guys finish planning, while Muichiro is sharpening his sword in his room. You knock on the door and once he slides it open, you all say "Happy birthday!!!" To Muichiro with those party noise making things (I'm pretty sure y'know what I mean by that)