It seems I didn't explain the castle selection procedure clearly enough. Let me clarify.
1. All participants must tell me which castle they will play with and against which opponent.
2. After I receive information from everyone, I will post it for everyone to see in the form of a table, i.e., it will be clear who is playing with whom and with which castles.
3. After that, you can start playing. Based on the castles, start sketching out your strategies.

Added 2 minutes later

We're playing the first match with Peterius today around 5:30 PM Moscow time, so anyone who wants to join is welcome; I'll do a broadcast.

Don't rush to start yet. Everyone needs to decide on their castles. You can, of course, start playing, but then the castles you played with will be known to your opponents, and you won't be able to use them in other games.