You should be interrested by a post sent by Kristoffer O. on the French PC4WAR forum
http://www.strataegis.com/forums/viewtopic.php?t=2691
Cheers

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Autosummoning:

10*(dom+growth+1) % chance (actually a d10 is used) of manikin reanimation if there are unburied corpses.
1+growth+magic% chance of mandragora - else manikin.

Also:

10*(dom+growth+1) % chance of carrion beast / pangaean manikin reanimation if the province is a forest.
1+growth+magic% chance of powerful stuff.

There might be some stuff prohibiting human manikin in forests (makng them beasts instead)

Reanimation:
Number: Priestlvl/2+(1D2-1)
Quality 10%

So, if you have ten provinces with dom5 (growth2+magic2) of which 5 are forests you would get about 9 manikin and 4 beasts each turn. Of these one or two would be powerful.