You have to stop the Conqueror's army here.
The battle starts with three Escort Teams, two Stormtrooper groups and two Assist Teams. The second wave of enemies - four Beastmaster groups - appears after taking the first one out, followed by three Mystic Squads when some of the Beastmasters are dead.
Finish them off to lure out the mini boss - a Beastmaster group with a Dragon (~270,000HP) - accompanied by two Stormtrooper and two Commandos groups. Two more Assist Teams together with a Stormtrooper and a Commandos group appear the next turn.
More reinforcements will come after each turn until you finish the mini boss (there is a limit to the number of reinforcements).
The fight ends when the mini boss dies.
- Gold depending on how many enemies you killed (approximately 46,784 gold if you kill every single enemy and wait out all reinforcements).