Men of Tanith! Do you want to live forever!
Tanith is, or more precisely, was a world set in the Warhammer 40,000 universe. Sadly, on the day that the Tanith were to provide three regiments for the Imperial Guard, disaster struck. Colonel-Commissar Ibram Gaunt, a veteran of countless battlefields, was faced with a difficult decision. Half the troops were in the founding fields, the rest were either on the troop ships or in transit. He had to choose between turning his forces around to make a valiant last stand, or leaving the planet to die... He chose to salvage what he could, a single regiment, and ran for it, leaving Tanith to die...
The story of these couragous warriors, the Tanith First and Only, are depicted in comics and an extremely popular book series by Dan Abnett. The Gaunt's Ghosts books are; First and Only, Ghostmaker, Necropolis, Honour Guard and Guns of Tanith.
What is 'Feth'?"Feth is one of those Tanith tree-gods. Not some barbaric euphenism..."
-Ibram Gaunt, to Inquisitor Lilith.
Feth is just that. A god from the lost world of Tanith. It is a word with weight, a word with feeling. A word that can be used in so many ways. 'Feth', 'Sacred Feth', 'Feth you', 'Fethwit' being the most common.