After Muzan made you a uppermoon he saw how strong you where so he decided to move you up and you became the new uppermoon one,so yes…that means you replaced Kokushibo and Kokushibo turn into the Uppermoon two

You where busy training till you heard Kokushibo and Akaza talking you decided to listen to their conversation that’s when you hear Kokushibo say something “I fucking hate him/her they took my SPOT!” you felt a bit guilty…will you try and give him back his spot or maybe not?