I'm fairly certain in the campaign, when on the samurai chapter, the further east you go into samurai territory the more rain forests and marshlands you run into. The trailer of the Wu Lin faction fighting was in a dryer, emptier landscape closely resembling barren deserts which is much more closely related to the western part of the knights territory. It's not that hard to draw that conclusion especially because one of the big details in that trailer was a literal sandstorm. I may be wrong about what the sandstorm represents but I like to think I at least know the different biomes based on the game play.