Undead

None encountered - yet!
They are the main object of the Universal Church's ire, and Wyldwood ain't too keen on them either.
The Elves dislike undead because they consume mana - though Eliezure suggested using death magic to create mana:
"I know that Eliezure has talked about careful harnessing of death magic but thankfully Sorlor and the council have banned him from experimenting further, from what we have seen so far the undead drain mana from the world and must be eradicated."Council Record Fragment 4
White Nightshade leaf preparations are used by the clans to protect against undead.
Day 65: One of the Centaur clans reported	finding a large, sorry huge, army of undead about 40 miles south of	Trollheim. The army was actually an ex-army, rotting corpses and their Orcish controllers torn to shreds, but nobody seems to have	any details on this;Day 65 - Far Haven - Tripwires
We have this info on them:Day 6a - Lunch with Vinmira A key point is that any largish group of zombies or skeletons (and presumably other Undead types) are likely being controlled by a nearby priest.
Party: It was said that trolls and orcs fight using undead. What can we learn about how these are created and controlled? 
Vinmira: “Only those that worship Temple of the Dead, we don’ use his name, have truck with undead. Small groups are fine, but there are tales of huge hordes bein’ pulled out of the old battlefields, an’ that will be a differen’ matter. Wynagh is the bes’ person to ask ‘bout preventing a corpse bein’ animated or the like – him being a Priest of Universal.”
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Vinmira: “These guys here were looking for some advice on preventing undead being created and also about the possibility of wound treatment”
Wynagh: “From what we know, the only certain way is through burning the corpse completely, and even then more powerful Priests of the Temple are able to pull the spirits of the dead to serve them. Thankfully most minor undead are relatively easy to deal with, but I suggest that at this stage if you come across any group of more than say 10 skeletons or zombies – you run – there will probably be a Temple priest or necromancer nearby. None have been seen in the region for years though.”