UPDATE: Added new spells "Conjure Empty Creature" (Adept) and "Empty Thrall" (Master) to summon the new creatures. They should be sold by all the normal vendors.

UPDATE: Added a new enemy, the Skullahan. These creatures are a mix of elements from the legends of the Dullahan and also the story of Vasilisa (http://en.wikipedia.org/wiki/Vasilisa_the_Beautiful). Basically they are unmounted, headless knights who carry a fire-shooting skull on a stick, which is as close to the Dullahan as I can make in a short CK session! They show up in vampirey places, just like the others, and they will be summonable too when I get around to making summon spells for them. In the meantime, you can collect their skull-sticks and wield them in battle yourself.

UPDATE: Helmhaunts shouldn't trigger pressure plates.

UPDATE: Made one of the new enemies spawn in Pinemoon Cave.

UPDATE: Now includes two more new enemies - Empty Monks and Helmhaunts.

UPDATE: They now come in a few extra varieties, appear in a few more places, and have an unholy smoke effect as suggested by Mr_Girr. No armour holes though - turns out that really doesn't work. More new stuff coming soon!

UPDATE: Now includes spells to summon them yourself! The tomes should appear in vendor lists and loot.