Board Thread:General Discussion/@comment-159.182.1.4-20130104174355/@comment-5896727-20130105000110

Unfortunately it is not, however, every decision you have made in the tutorial (side and leader) is not important in the later game, as you get to play every campaign and are able to collect the other "leaders" as well.

I once asked the support whether or not it is possible to reset the game (because I was worried about my decision), but they also told me that it is not and if I want to I have to make a new account.