Rising Thunder is a free-to-play fighting game that was previously in a closed network test where only a limited amount of people could play, but now it is open and available for everyone. All you need to do is sign up and download the game.
I’ve personally did a few tests with the game and the online is very solid. There’s also a training mode you can go to in order to get a better feel of the characters. You can find the official website here.