I've seen bonuses that are given when you have a certain ability; maybe it can be applied to armor and a couple of other skills. It gives +1/1 and, at level 20, +2 to defense if you have defense and +2 to attack if you have attack.
And is it possible to enhance the counterattack at all? And can you enhance the hero's attacks with this ability?
I also don't understand why the Cerberus's speed was reduced, or if it was reduced at all?
In the future, I would advise you to take some things from UNIT. There are many good changes there, but the best ones are:
-Swapping griffins and monks, hydras and witches, bears and bone crushers
-Buffing demons and Cerberuses
-Nerfing leaders
-Ice dragons
-Imperial archers
-Buffing dragons in Necropolis
-Buffing undead