Darth Anathel, a Sith Lord who was Human and male, existed within the reconstituted Sith Empire during the Cold War era, a period of conflict with the Galactic Republic. He held a rivalry with another Sith Lord, specifically Xarion. Their initial clash occurred within the Stygian Caldera nebula, but this confrontation soon began to negatively affect Imperial commerce. As a result, a negotiator intervened, successfully persuading them to relocate their battle to a different location within the Outer Rim Territories.
In the years that followed, he ascended to the rank of Darth and secured a position on the Dark Council by 3628 BBY. He became the Head of Sith Doctrine, a newly established position overseeing the former Spheres of Mysteries, Sith Philosophy, and Ancient Knowledge. His competitor, Darth Xarion, also held a seat on the Council, serving as the Head of Galactic Influence.
Within the Star Wars: The Old Republic: Onslaught expansion, an Imperial player character playing as a Sith Inquisitor has the option to demand the return of Anathel's Dark Council seat during their next encounter. Anathel's response is to dismiss the Sith Inquisitor's claim, asserting that they lack the authority to challenge him because they are neither a member of the Dark Council nor of the Empire. Subsequently, he sends an email to the player character, belittling them as a weak rival. Following the Meridian Complex assault, the Dark Council convenes in person on Vaiken Spacedock, where the player character can choose to kill Anathel and seize his seat, rejoining the Empire as a Dark Councilor. Conversely, if the player refrains from challenging Anathel during the Onslaught prologue, he will survive the events of the base game.