The castle is said to be haunted by the ghost of Erilda, with her terrified form being chased through the ruins by the demon said to have slain her. The demon deceived Erilda by taking the form of a knight with a red plume.

The apparition of a man wearing “a cloak and a wide-brimmed hat” and covered in mist was witnessed outside a house near Rhuddlan Castle.

A lane that runs between the castle and Twt Hill is said to be haunted by a number of “terrifying apparitions” that include a group of “dwarfish men carrying picks and lamps. They spoke in an unusual language when the witness encountered them in the 1950’s. However, what frightened him more were the three faceless seven-foot tall cloaked and hooded figures that led them. They barged him into a hedge where he passed out with fright. In the 1970’s, archaeological excavations conducted in that location by the University of Exeter revealed the site of a Norman Church - and the grave of a very small man.