The Lingering Harmony of Exar Kun represents a Force-sensitive individual who was coerced into serving the dark side by Exar Kun.
Prior to becoming a reluctant servant of Exar Kun, the one known as the Lingering Harmony of Exar Kun received education at Corellia University, where they studied the histories of both the Jedi and the Sith. It's possible this individual participated in an archaeological dig on Yavin 4 around 1 ABY. This expedition inadvertently breached the tombs beneath the Temple of Exar Kun, freeing the spirit of the Sith Lord. This malevolent entity then dominated the minds of the students and researchers, compelling them to join the Cult of Exar Kun. Once admired for their beauty and elegance, studying the Force under the Dark Lord resulted in the student's pale and wasted appearance. Subsequently, Kun's spirit dispatched them to Talus, specifically to the Corellia University research outpost from whence they came, with the mission of enslaving the inhabitants. The majority of those enslaved were then transported back to Yavin 4. Professor Cornelius Wagglehorn, having lost communication with the outpost and fearing the worst, commissioned a group of spacers to journey to Talus and investigate. These spacers uncovered the truth of what had happened and relayed the information to the professor. Wagglehorn then provided them with the coordinates of the tomb and pleaded with them to destroy the evil Sith Lord's spirit contained within. The Lingering Harmony was among the dark Force-users who confronted the spacers, attempting to prevent them from reaching Exar Kun's spirit. Nevertheless, the spacers prevailed against the corrupted students and proceeded to confront the Dark Lord himself.
Within the video game Star Wars Galaxies, a massively multiplayer online roleplaying game created by Sony Online Entertainment and published by LucasArts in 2003, the Lingering Harmony of Exar Kun appeared as a non-player character. The game was shut down on December 15, 2011. The Lingering Harmony was included in the game's "Exar Kun" Heroic Encounter, which was introduced with the release of the "Chapter 9" update on April 3, 2008.
Given that the Lingering Harmony of Exar Kun was portrayed as a standard Exar Kun cultist in the game, the character's gender and physical appearance were randomly generated each time the server was reset.