A mod like this can be created by hand in just 10 minutes. You just need to tweak the Defaultstats file.
I know where the file is. (data\GameMechanics\RPGStats)
But I prefer to ask knowledgeable people what exactly needs to be done, rather than experimenting myself.
P.S.
I see, I guess this is the work of a castle transformer:
(I don't see a "spoiler")
CREATURE_PEASANT
CREATURE_SKELETON
CREATURE_MILITIAMAN
CREATURE_SKELETON
....
But I need the undead to be raised using dark energy.