How do Factions work?

There are 4 factions in the game, and each one has its own unique bonus and advantage over another faction. Each faction deals 25% more damage to one other faction, so it is very important to prepare properly for each battle. Here is the advantage chart:

To find out which troops you will face in the next battle, click the information button in the battle preview window:

We can see that the next battle will mainly feature Federation and Empire troops, which means the best choice is to use Federation or Union troops.

If you choose factions that deal extra damage to the enemy, this will be shown: