Hex
Background
Hex is an artificial intelligence computer at the Unseen University in Ankh-Morpork, on Discworld.
During the events of Terry Pratchett's Hogfather (2006)
Ridcully talks with Ponder Stibbons who shows him Hex. Ridcully asks Hex about what is going on and while they are waiting, a Hair Loss Fairy appears on the head of The Dean. Ridcully asks Hex where the Tooth Fairy's castle is located at. He then asks Hex again what is going on and Stibbons tells him he thinks what they are getting are personification of forces. Hex says new creatures are appearing due to some beliefs disappearing. Later, Death asks Hex questions and Hex tells him only regular and consistent belief will save humans. Death asks Hex if he believes in the Hogfather and Hex takes some time, but says yes and then asks for a present.