Mistakes when playing as Humans.

The Warlock's defense is generally a weak point. If you're unlucky, you might end up with 0 defense at level 20! If you level up a Knight in arenas and choose artifacts that boost attack, the Knight's troops will deal significant damage to the Warlock. It's best to play for as long as possible – as levels increase, the value of Chaos magic decreases. And in general, preparation is key!