This is, to be said,
Amazing. Ailikit. 
Honestly, since no one looks at arena this could easily be a casual roleplay and get much more interest- but hey, that's up to you.
I'm interested, at least.
One question-

"-You can only make ONE move each post"
Does this mean, one post per turn, or you can't dodge and swing a sword in the same turn? It's ridiculous if you can't, and I'm going to take my leave if you can only do, as it says, one move per turn.