What kind of magic do you like?

Well, here everything depends on the first move. If it's a Mage, cast Hypnotize on the Druid, and the rest is obvious. If it's a Necromancer, cast Hand of Despair on the Sorcerer. Then, the Mage casts Hypnotize or Blind on the Sylvan, if it's their turn. If not, the Sylvan casts Anti-Magic on themselves. Then, the Mage and Necromancer wait for the Sylvan's turn. No matter what the Sylvan summons, we cast Illusion. And Hand of Despair on the original target. And we repeat everything.

If the Sylvan goes first, we cast Anti-Magic on the Chaos Knight. A Chaos Knight with full magic resistance is useless; there's no need to explain. If it's a Chaos Knight, there's a whole set of tools to kill it. Either, if the heroes are standing close together, cast Confusion Cloud, and then the praying mantises will fly in and we'll cast Disintegrate...