This page lists the main differences between Disney's The Black Cauldron and the books The Book of Three and The Black Cauldron. It is not meant to be exhaustive; readers should feel free to add additional differences as appropriate.
In the main, the animated film is an amalgam of the first two books in the Chronicles of Prydain series, with The Book of Three forming the chief narrative structure, plus key elements from The Black Cauldron included: Hen Wen is pursued for her putative power over the Cauldron (rather than for her secret knowledge of The Horned King; the Witches of Morva possess the Cauldron as in the second novel; and the magic swordis Taran's prized possession instead of the Brooch of Adaon.
Main Story Differences
- The Horned King is both the ruler of Prydain and the main antagonist rather than Arawn.
- Arawn is a spirit trapped in the Cauldron.
- A magic sword similar to Dyrnwyn appears, but is not black and is not named.
- The Horned King's castle is a main locale, from which the characters must escape and in which the climax occurs, rather than Spiral Castle or Annuvin.
- Instead of Ellidyr sacrificing himself to destroy the Cauldron, Gurgi performs the sacrifice.
- Princess Eilonwy has "dirty blonde" hair rather than "red-gold" hair. Her bauble floats instead of being hand-held.
- Dallben has no beard and is bald.
- Fflewddur Fflam is elderly, portly and cowardly rather than middle-aged, slender and brave.
- Gurgi is small and resembles a lapdog rather than being large enough to wield a sword and bow.
- Hen Wen is tiny and pink instead of an adult white sow.
- The Gwythaints are small dragons or wyverns, rather than eagle-like birds.
- All of the Fair Folk are miniature, moth-winged fairy-people, including Doli.
- Orddu, Orwen, and Orgoch are loud and obnoxious rather than clever and subtle. Orwen is inexplicably attracted to Fflewddur.
- The Cauldron-Born are skeletal warriors rather than fleshed as in the books; they appear only briefly near the climax of the film.
- Creeper is an original character to the movie.
- There are no Huntsmen of Annuvin; the Horned King's henchmen are standard warriors.
- The following key characters from first two novels do not appear: Coll, Gwydion, Achren, Adaon, King Smoit, Ellidyr, King Morgant.