I guess this would be possible if you are not going for a no-loss game and the only requirement is that you fight all battles and win them.
If you have Eviln and the Burial Mask (+2 defense, -20% leadership of zombies) then undead units to consider are:
Skeleton Archer
Zombie
Decaying Zombie
Let's not forget the no-retaliation, fireball-throwing imps:
Imp
Scoffer Imp
And of course, some power-puff girls:
Lake Fairy
Forest Fairy
Dryad
It's definitely possible to win and complete, but as a no-loss? No thanks, I'll pass.
