The most useful unit upgrade.

It's a pity the Renegades weren't finished, although maybe I don't have all the patches installed (need to upgrade up to 2.1 again), but at this stage their troops don't synergize with the Castle and heroes; that is, if you upgraded a warrior into a renegade, you can no longer train them. I agree that one should take more non-upgraded warriors, but for some reason my "buy all" button always precedes that thought, and hero bonuses don't work on these troops either. Just recently I played as a griffon trainer: the non-upgraded ones strike from the skies and receive defense and attack bonuses, while the "upgraded" ones do neither. I hope this is fixed in the patches :) Otherwise, there would be no stopping a renegade griffon; it would get bonuses, have the dive attack, and its "native" skill would be very appropriate—it would be an absolute powerhouse :)