[Zechnophobe]

I would say Reds are best as well, followed by blacks. As much as you can't heal blacks, they also have the best resistances in the game, being 'immune' to two different damage types, and still having innate physical resistance.

Red's though, are almost as good... and you can Phantom them, stone skin them, timeback them, etc.

I think that a lot of the level 5 units in this game end up being more worth it than in TL. The Archdemon 'halve' ability is very impressive, especially in boss fights. I just wish Humans had a level 5'er. Screw Titans, I want Seraphs or Archangels or ... something. Maybe some sort of 'hero'? Not sure what would fit the KB lore best.

Edit: Oh, and Shield of Rekross is better than Call Colossus, as it will provide you with dragons of various types for many levels to come, whereas the scroll will give only a couple early on.