Since the game follows a rock - paper - scissors mechanic, meaning that one element is strong against another and weak against a third, when building a generic team, you should try and mix up as many elements as possible. I repeat - this advice doesn't go well for when you try to specialize, but specializing early on is risky because you will face various types of enemies throughout the stages and generally, especially early on, you won't have a lot of great heroes in each element to choose from. So instead I would say that it's a lot better to build a team with one of each elements, selecting the best hero from each. In reality, you will probably end up having two out of your starting five of the same element and the other three different. If that's the case, make sure that you get the wildcard (the second commander which is usually coming from a friend) of the element you don't have.