Tactics and strategy in Heroes of Might and Magic V.

This is true if there are Chaos castles on the map that you capture. And another problem for a Knight with Chaos is usually their low magic level.

In this case, Chaos spells aren't for damage. Fireball reduces the target's defense by 50% for one turn. And Freezing Cold freezes the target and increases the damage dealt to it. Plus, the 20% damage bonus, as I mentioned, is also quite significant. And considering a developed Empathy skill, which I think is essential for a Knight, he will cast spells often.