In my opinion, Necropolis has two dangerous opponents: Rampart and Dungeon. I don't understand why they don't allow playing with Knight; his stats aren't that impressive. I delete Flax first with my Sorceress because of his cheating Bird growth, and I don't even know how to play him well, even after playing with Pit in the expansion. All of this is true for single-player, of course.
Knight is the second strongest in terms of starting army strength (+buying units from the castle on day 111), after the Шахтёр.