The most difficult alternative

I mean that when playing as Haven in captured, undeveloped Chaos castles, it's more advantageous to build Hydras. They have the same illusions and teleports. With a Nature and Life mage, you can teleport into the thick of the enemy, followed by an Angel of Light and Antimagic from above. Or another set of spells, depending on the opponent, but always starting with teleportation. With a Haven mage, you can never drown a Hydra or Naga in sand. ;)