The main problem about harder is within the first two weeks, all the zombies immediately make a beeline toward your fort, and make everything pretty damn near impossible.
i think i killed akron in epic mode once.
Best advice i have is get all members to the point where dark does nothing, cause he has no massive attack that does insta kill damage that isn't dark.
plus, if dark does nothing, u could let the cosmic monoliths blast everything for damage, and sometimes they will damage akron with that blast as well.
You're supposed to have high health if your opponent uses freeze defense, and in fact all the mages have the ability to counter freeze defense except maybe great sea.