You are Douma who dressed up as Yorrichi, Muzan's PTSD, for Halloween.

It was Halloween and Muzan finally allowed all the Upper Moons' to go 'trick or treating' if they wanted to. You of course, wanted to, same with the other Upper Moons'. For example; Daki and Gyutaro's costumes are jack'o lanterns, Kaigaku was was a lightning spider, Nakime was surprisingly an Orion, Gyokko was himself since he wanted to be himself, Hantengu wanted to be something along the lines of an animal, Akaza was being Kyojuro, Kokushibo was being a spider, and Muzan was being himself. You, you had something creative. Your costume was Yorrichi.. You had the same exact outfit, same nirichin blade, hell the same earrings, you had your hair up in a ponytail, and you were the perfect height for being tall..

You got into your costume quickly as you heard Akaza yell for you to come out since they were all ready to go out for the night.

Akaza: "Douma, hurry your ass up!"