The king wanted to test if he could still keep up with his age, and wanted to see your strength in the opposite side's view. He said he won't bring any powerful units, but it will be filled with action.
Enemy deck :
Miners, Magikills, mana burst, spiritons, zombie apocalypse, king zarek. and 2 other cards(probably something like Vault of prudence and speartons)
The enemy would start with the king already on training, the king or the enemy ai in general will attempt to keep hold and stay at the center tower, they will only attack when the center tower is at lvl 4, when the king is down they will retreat in front of their statue until the king respawns.
Since the king does not want any harm or win, magikills won't cast fulminate on ground units and the center tower zap is disabled.
And I want to remind that we still don't have a profile avatar of king zarek.