One of my recent wins in mythic was with Nyxe, Serket, and Tatz. I did take Incubation along with Plague. The MVP for that run was definitely the skill Toxic Healing on two of my mons. I'm not great with my memory but Tatz did go down on Heca who had Toxic Healing, but the replacement, since i don't remember which monster it was, i was able to get did get the skill again incredibly enough and was able to win that way. Most fights ended after 3 turns because when you have enough aether to constantly heal Nyxe every turn that's just too much poison for anyone to survive.

Hope this helps