The Undead are any kind of supernatural being that is no longer alive but not truly dead. They are divided between corporeal entities (those with physical form) and ethereal entities (those that are spiritual and without physical form).

Known Undead Species

• Corporeal
  • Liches
  • People of the Deep
  • Revenants
  • Skeletons
  • Wights
  • Zombies
• Ethereal
  • Apparitions
  • Haunts
  • Phantoms
  • Shades
  • Sky Phantoms
  • Specters
  • Wraiths

Source

• Fablehaven (Fablehaven #1)
• Rise of the Evening Star (Fablehaven #2)
• Grip of the Shadow Plague (Fablehaven #3)
• Secrets of the Dragon Sanctuary (Fablehaven #4)
• Keys to the Demon Prison (Fablehaven #5)
• Dragonwatch (Dragonwatch #1)
• Wrath of the Dragon King (Dragonwatch #2)