Sir Hugo de Giffard was known as the ‘Wizard of Yester’, and was considered to be a powerful warlock and necromancer. It is in the undercroft of the castle that he was thought to practise his sorcery. 14th century chronicler John of Fordun mentions the large cavern in Yester Castle, thought locally to have been formed by magical artifice. Legend supposed that Hugo was able, via a pact with the Devil, to raise a magical army to his aid, and use them to carry out his will. It is this army of hobgoblins that was considered the builders of Yester Castle.
In this location, during investigations and observations by a plethora of enthusiasts into all things paranormal, various noises, EVP and weird sensations have been evident.