An ancient Sith Lord, known as Andeddu, inspired the saying "Andeddu's flames." During the Galactic Empire's reign, Darth Vader's servant, Vaneé, a Sith Lord's aide, invoked this expression when vowing to recapture Rebel Alliance Lieutenant Thom Hudd. Hudd had previously escaped from captivity within Vader's castle situated on the planet Mustafar.
Years afterward, the Sith Eternal, a cult comprised of Sith loyalists active around 35 ABY, named their Sith trooper units after ancient Sith Lords. Consequently, the Andeddu Legion received its designation from Andeddu, a figure whose history was concealed from the wider galaxy.
The initial mention of Andeddu in current Star Wars canon occurred in Star Wars Adventures: Return to Vader's Castle 2, a comic book penned by Cavan Scott and published by IDW Publishing on October 9, 2019. Darth Andeddu's character originally appeared within the Star Wars Legends continuity in Republic 63. This comic book was written by John Ostrander, with illustrations by Jan Duursema, and was released by Dark Horse Comics on April 7, 2004.