Complex sentence: In the game's storyline, all three characters fight the Dark Alliance together, however, all three characters are only playable at the same time in ports of the game on the Nintendo Gamecube and the Xbox.
Split into simpler sentences: In the games canon storyline, all three characters fight the Dark Alliance together. However, all three characters are only playable at the same time in ports of the game on the Nintendo Gamecube and the Xbox.