Warlocks learn magic for the power it gives them to achieve dark and selfish goals. More than any other hero, they focus on the pursuit of magical knowledge over other values. Warlocks often flaunt their power, using magic to alter their features.
When levelling up, warlocks are most likely to gain spellpower (50%) and knowledge (40%), and less likely to gain attack and defense (5% each) for the first ten levels. After level ten, it's 20% each for attack and defense, and 30% each for spellpower and knowledge.