You have just turned into a demon. After years you finally got powerful enough to be a Lowermoon and then later 10 years you finally became a Uppermoon. After muzan introduced you and finished the meeting. You're left in the infinity castle with them all and you can talk to them or leave

Daki & Akaza They were Talking to each other and gossip a lot about stuff

Kokushibo: He was just sitting there in his thoughts

Douma & Gyokko: Doma was complementing Gyokko's pot as gyokko thank him

Gyutaro: Just standing there doing nothing