Wain counted on Lich to make that mistake and use all his forces at once. This allowed Wain to get rid of all his problems in an instant. His plan was risky, but he succeeded. His plan consisted of three steps.
First, Wain lowered his enemies' stats by equating their strength to the average of everyone else's. Then he used Seal of Dark Light and increased his attack significantly, and finally, he used a powerful artifact that summoned light rays.
Since the Death Knights and the beasts were undead, this attack was fatal for them. Lich understood this, so he tried his best to save his subordinates.
The crystal on Lich's staff glowed brightly, and a massive seal of blue flame appeared above them. It absorbed the rays of light, but it could not last. Cracks gradually appeared in the seal, and Lich's powers quickly dried up.
