- Duffin MacDuff
The MacDuff clan is located in the center of the southeastern part of the Beyond .
The land is north of the MacNab clan, southeast to the MacDonegal clan, the MacAngus clan, and the MacHeath clan. The MacDuff clan is southwest to the MacDuncan clan, the MacNamara clan, and the Ring of Sacred Volcanoes.
In Lone Wolf, the MacDuff clan's chieftain, Duffin MacDuff, went to a meeting with the other chieftains and was actually the one who suggested the Sark of the Slough. The clan chased Faolan to the wall of fire at the end and when Faolan jumped over it, they immediately started rumors.
In Frost Wolf, the MacDuff clan may have been wiped out due to famine and Skaars Dancing. Creakle, a gnaw wolf, is thought to be the last MacDuff wolf. He is not mentioned afterwards, although it seems unlikely he survived the earthquake at the beginning of Spirit Wolf.
- "MacDuff" comes from the Irish word "Mac" meaning son, and "Duff" an old Irish name meaning black or dark. All together this means Son of the black/dark man, or Son of Duff.
- The clan may be named after Macduff, a character in Shakespeare's Macbeth.