The first avaiable challenge, and although you'll be able soone to wrack havoc around it, for starters this is a challenge.
It has 2 stages, meaning you have to beat two levels to get your reward (fliping cards). The reward is usualy some green gem, low tier ogres, Elemental Equipment (begginer stuff), low tier goblins, or low tier bats.
The enemy are made of low damage goblins of high HP, good damage low hp poisonous melee goblins, and the most dangerous high damage, high HP, poisonous archer goblins. For the second stage they get Bombs too, which deal the exact same damage as the barells scattered here. These Bombs are better left alone if they reach the players, as they don't do damage without exploding, even with buffs on their head.
The extra stuff at this challenge are some barells which blow up causing elemental damage when destroyed. These can be used for tactical advantage.
Initially the bosses will throw some Fireballs on you, and they have Poison too. During the second stage the boss can also cast Fly on massive amount of members of its horde, what can lead to quite dangerous situations.
With the incrising of difficulty the Bombs/Barells will do incrising damage making it practically impossible to survive for a melee unite, as well as all enemy units gain extra HPs making them harder to dispose of.
The reason people will always come back to this scenario is the fact that on Easy setting your party get AI allies at every empty place for Heroes. This makes the daily Guild-quest for killing a boss way easier to complete, because you need only one other member of your guild to win and gain the quest.