In BattleSouls, you join the battle for the legendary soul crystals. As part of a team you engage in fast paced melee and ranged combat in order to destroy the other team's soul crystals before they destroy yours.
To accomplish your objective you bring a loadout of three heroes, each with their own unique skills and playstyle.
In battle, you can freely switch between them in order to activate your passive skills and adapt to your current situation.
Source: The Game Website.