I started working on this game in november 2008. Back then, it was supposed to be a flash port of Tetra Master, the card mini-game in Final Fantasy 9, but halfway during the development, I thought "hey, why not spice it up and make my own game?" and so Ethereal Masters was born. I'd like to think it's a bit more original. Also, I would like to thank Ryan "Rtil" Miller for letting me use his work for the cards. I could never have done it alone, or anyway it wouldn't have looked nearly as good =P
You play as a newcomer in the Tournament whose goal is to rise to the rank of Champion. The gameplay is very similar to that of Tetra Master; you and your opponent get five cards which you must place on a 4x4 board. You can attack and capture the other player's cards depending on where they're placed and their attack and defense power. At the end of each round, the player who has the most cards in his possession wins. You can get new cards throughout the game and gain experience to make them stronger. The rules are detailed in the tutorial.
Edit: Fixed the level-up system. Now the side which gets upgraded is totally random, so it's now very unlikely that you'll end up with large arrays, and it stops only when you're at 15-15. Sorry for taking so long to fix this issue.
I hope you have as much fun with this game as I had making it. Good luck!