Tengen's birthday

Gyomei, Sanemi, Giyu, Obanai, Shinobu, Mitsuri and Muichiro all got an emergency meeting letter and were now standing in a dark room with Tanjiro, Nezuko, Inosuke, Zenitsu and Kanao, who just got invited to meet there, all of them arguing about what the reason was except it being Halloween, then fireworks blew up outside the room and neon lights went on, music started playing, the room got lighter, and Tengen and Kyoujuro went in with sparklers, then the party began