The Black Harbingers of Ermgard have learned to cheat death. Alas, their mastery over death is not sufficient - they can hold on to the mortal world only until they have avenged their deaths (ie until battle ends)
The Azure Priors of Helder are able to turn into horrible beasts of the depths. In this form their affinity with water magic increases, but they lose power in all other magic paths (the unit in picture happened to get a water random)
The Divine Elders of Kongtala are able to travel fast in their fearsome turkey form. This does not hamper casting.
Bavarainean Keepers have mastered death. Their foul magics will raise them as ghouls upon their deaths, but this works only once - if the keepers are slain again, they will stay dead (this might be overpowered, it gives +30g cost now though)
Other forms currently implemented include: devil, frost fiend, great bear, wolf, werewolf, jaguar, and winged monkey. It's very easy to add these from .txt files.