In a sense, the "arena" of the Guild is exclusive to members of that specific guild. This battle area lets you fight up to 5 times for free (only wins count as an entry) and then costs 12 energy per win after. If you lose, no energy will be spent. Each team starts with no Rage, however, health carries over. Heroes that can heal are recommended because your heroes don't regen their health normally after battle. Depending on how much Rage a hero has post battle, it will slightly heal them up to 20% at 100% rage, +10% health at 50% rage, and etc. Rewards of Guild Bux and Guild Points (GP) increase as you consecutively win starting with 3. After all your heroes die there is a cooldown of 1 hour before they are all revived again. Alternately, you can pay 100 Gems to revive them right away, which increases to 200, 300, and so on.
Recommended Heroes
Picking a team that is a bit heavier on the support and healer side will provide you the buffs, boosts, and sustain to defeat the enemy team and go on to fight others with that team.
Healers
Tanks
Nukers and Supports
Diablers
NB: Heroes can assimilate a similar role will do fine, especially if you need to substitute one out in case of death. These are generally recommended to obtain the most Guild Points and Guild Bux.