If you want to continue playing Closers and keep all your stuff, you’re going to have to do that whole migration thing and move your account from En Masse to Naddic’s system. And yes, this is something you’re going to have to do, Naddic’s not doing it automatically.
So, how do you go about doing this? It’s a fairly basic process that starts with you logging into your old En Masse account via the migrations link. Then you’ll need to read through some information and check a few boxes consenting to have your information transferred. After that, you click the “Start Migration” button and let it do its thing.
After that, you should be good to continue playing the game and have your stuff, too. You may just want to check the FAQ on the post though to make sure you understand what transfers and what does not.