Stars are used to unlock a new random hero and upgrade bonuses. Stars are obtained through single player missions and PvP. Getting stars in mission depends on how hard the mission is or if the player fulfill a certain requirement. Stars earned on PvP is based on the difference of PvP points. The fastest way to get star is playing skirmish in two different devices against each other and disconnecting in the middle of the game, this will result both player to get stars.