Best level 6 unit.

Oh, and I forgot to mention something. Basically, when you take mentally unstable (level 6 Conflux of Elemental) creatures into battle during the first or second week, don't get too excited about the prospect of easily defeating the Necropolis. They deal very weak damage to Necropolis troops, inflicting only half damage. So be careful, otherwise you might end up losing a significant portion of your army (even if it's not the hero himself).