Felkor

Felkor was a Sith Lord who was depicted in a statue chiseled into one of the interior rock walls of the Sith Citadel on Exegol, a Sith planet in the Unknown Regions. By 35 ABY, Kylo Ren—former Jedi trainee, Master of the Knights of Ren, and the Supreme Leader of the First Order—had become familiar with Felkor as part of his studies. That year, when Ren arrived at the Sith Citadel in order to investigate a mysterious transmission from the supposedly-deceased Galactic Emperor Palpatine, he recognized Felkor and other Sith Lords in the statues of the edifice. As he advanced into the interior of the citadel, Ren heard unintelligible whispers from Felkor's effigy and the others despite their mouths not moving.

Text and facts from the “Felkor” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.