TEXT: Dullahan
  Mutilated by or in death, the dullahan rise from the 
  grave headless with the torturous obsession of making 
  themselves whole again. The dark powers that bring a 
  dullahan back from the dead also prevent a dullahan 
  from ever finding its own head though it spends it 
  unlife searching for it in vain and taking the heads 
  of others in a fruitless effort to return to the peace of 
  death.. Summoning up hellish mounts, dullahan riders 
  chase down the members of vulnerable and isolated 
  communities one by one building up a collection 
  of severed heads, each one serving as an imperfect 
  reflection of the head that might bring them peace.
  Hall of Heads. The dullahan typically keep one or 
  more isolate or secure locations where they keep heads 
  they have severed and stolen from others. A dullahan 
  rider can perform a dark hour long ritual on a full moon 
  to animate one of the severed heads. He cannot perform 
  this ritual if he already has a animate head. Until it is 
  destroyed the animate head flies after the dullahan rider 
  muttering curses, screaming in terror, and doing the 
  bidding of the dullahan.
  Peace or Pain. There are only two ways to 
  permanently kill a dullahan: destroy its animate head 
  and its body at the same time or return the head the 
  dullahan had in life to the rider. By destroying the 
  dullahan rider’s animated head and body at once, the 
  dullahan is condemned to a purgatory of suffering and 
  longing for his body to be made whole. By reuniting the 
  dullahan with the head it had in life, the dullahan flees 
  to a quiet place and lays himself to rest for good.
  PDF compiled, edited and designed to resemble the official Monster Manual by /u/Barkalot
  Dullahan
  
  Dullhan by
  /u/ coolgamertagbro
  http://sterlingvermin.com/
  Art Credits in Order of Appearance
  “Dullahan” by slim mittens
  Dullahan
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/5th Edition (5e)/3rd Party/Benjamin Huffman/Dullahan.pdf