These are created by<fill in you local evil cabal of wizards> for $. they are surprisingly easy to create by using the blackest of souls. they come in several varieties
Wizard-offensive magic caster
Warlord- front line Sgt.
Arcane adviser-mystical advice for your would be world conqueror
Hexer- magic debuffer
highly intelligent low ac and vulnerable to fire
They make great plot hook. They are widly spread and common amunst evil forces. Who is making them? Can you cut off the materials needed to make them