Coop - Campaign where you can only invite alliance or friend, The person who invites gets the choice of the 5th hero . Your team totally power and hero’s will be constructed to fit the power of enemies on the map of your choice.
This is for game play, (gives another game play option besides pvp). Also this a Expreince boost for lower lv players gives them an outlook how to better understand team blance.
Of course you must have level unlocked in order to play.And no rewards besides xp and cash. For the cost of your stanima to play. Just an ideal.