The Fanghur are a species of reptilian native animals of the Beor Mountains and they were commonly known as wind-vipers. The are distant cousins of the dragons, though the are less intelligent and cannot breath fire. The Fanghur are the sacred animals of the Dwarf Clan, Dûrgrimst Fanghur, despite the fact that are least the dwarves of Dûrgrimst Ragni Hefthyn apparently think of them as pests, due to the fact they sometimes known to attack and feast of the dwarves' Feldûnost.
Fanghur resembled giant serpents around twenty feet in length, with leathery wings similar to those of dragons, but smaller, could not breathe fire, as well as were less intelligent than dragons. They had dappled green or brown scales. They stunned their prey with an immobilizing mental screech and then killed them. They usually hunted in groups of three or four. Dragons and Fanghur are distant cousins, but are less closely related than Dragons and Nïdhwal (sea-dragon), despite being to the air, while the Nïdhwal are to the sea.
The Fanghur were extremely endangered during Eragon's time. When traveling from Tarnag to the Âz Ragni, Eragon and Saphira were attacked by a group of three Fanghur, but thanks to Saphira's strength and fire, the Fanghur were scared off, with one being injured. Arya then commented that they would be sorely missed if Saphira had killed them, implying they were highly endangered. The Dwarf clan known as the Dûrgrimst Fanghur (led by Grimstborith Havard at the time of the Rider War) are named after them.