- The prologue states that Arawn Death-Lord is a spirit trapped in the cauldron.
- The Horned King is the ruler of Prydain rather than Arawn.
- He is the main antagonist rather than a minor character.
- A magic sword like Dyrnwyn appears, but is not black and is not named.
- Instead of Ellidyr sacrificing himself, Gurgi performs the sacrifice.
- The story is basically The Book of Three (novel) with Hen Wen pursued for her imagined power over the cauldron, with the Witches of Morva tacked on, and the magic sword in place of the Brooch of Adaon.
- Princess Eilonwy is blonde as opposed to having "red-gold" hair.
- Dallben has no beard.
- Fflewddur Fflam is elderly and portly.
- Gurgi is small and dog-like.
- Hen Wen is tiny and pink rather than a white, adult sow.
- Doli is a tiny, crotchety old man with a gray beard and moth wings.
- All of the Fair Folk are miniature, moth-winged people.
- Orddu, Orwen, and Orgoch are loud, obnoxious and unsubtle.
- Creeper is not in the books; he is an original character.
- Eilonwy's Bauble floats.