I was just reading the battle part of the rules, just for fun, when you ran into the following rule:
IMPORTANT: If you have a skill that somehow affects the deckbuilding of your opponent, you are responsible for letting your opponent know about this at least 12 hours in advance. If you do not inform your opponent about your skills in time, those skills will not be included in that battle.
Even though I can see the reasoning behind this rule, it might cause trouble when only having 48 hours for each round.
For example: I send a pm to Bill, telling him I am champion of water, and telling him I'm available 3 to 8 hours from now and 27 to 32 hours from now.
Bill answers (directly) saying me that he is able to fight in 7 to 10 hours from now and in 33 to 35 hours from now. Of course we will than schedule the match between 7 and 8 hours from now, but that means he can claim I hadn't informed him in time.
This could lead to people disrupting the battle because the person with the skill wants to have it done quick, while the person without wants to drag the match until after those 12 hours have passed, which could easily result in matches simply not happening.
Problem is, I can see that you will have to inform you opponent about your skills, and in time, so he can react to it, but on the other hand, it can cause problems with scheduling the matches if there is a set time. I can't see a way to fix this though, because just saying something like: "it is your duty to inform you opponent about any deck affecting skills beforehand" will lead to people waiting until one hour before the deadline, when they are both online, then telling the specific deckbuilding rules, and watching your opponent build decks in 30 minutes, to play the match in the other 30 minutes.