Strategies for Rezo battle

[Ashaman]

I dont understand what some ppl talking about, maybe they used some bugs or idk what. I tried the undead in mage tower at 30th level with 10k leadership, but it is impossible. 2x 5k skeleton archrers are quite enough...
I try it with engineers, and blind the skeletons twice or more, but there are 400 cursed ghost x2, and about 400 ancient vampire, it is not posible in that moment...