The eternal emperor, Valkorion, is the leader and founder of the eternal empire, and sith empire spanning over 1700 years. Sustained for centuries by his force abilities he quickly overthrew all opposing enemy's at a young age then created and ruled over two separate empires for centuries before finally being killed through his own sons betrayal. Before his time as the Immortal Emperor he was known as the sith lord Vitiate. He lived for 1300 years as the sith emperor, inhabiting a body his spirit had possessed. Even before his time as a sith lord he was known as Tenebrae, A sith pure-blood. His father was a powerful sith lord who ruled over their plant, and illegitimately fathered Tenebrea to a poor woman on the outskirts of their home. Tenebrea's father returned to confront him after he had begun to carve a path of death and destruction at the age of ten. Even at his young age Tenebrea overpowered and severed his father connection to the force and imprisoned his spirit for a millennia, conquering his home world and starting his reign over the galaxy.
Valkorion, through his millennia of life had experience that outmatched all others in the franchise. Even some of the most brilliant minds including the likes of Revan, Luke Skywalker, Grand Admiral Thrawn, and even Emperor Palpatine, who was responsible for the downfall of the entire jedi order and republic, did not have the prowess that Valkorion held. As the commander of the Eternal Fleet Valkorion became a threat to both the republic, and the sith empire. Unbeknownst to either side was that he had been orchestrating the entire galaxy for the past millennia. Aside from being the greatest mind in the series, he was one, if not the most powerful force wielder in the franchise. strong enough to make voids in the force, areas that have no presence of the force and subsequently leave both Jedi and Sith powerless.
As powerful as he was, Valkorion did fear one thing, death. His fear of death controlled him and in response to that his only goal was to become immortal, even at the expense of the entire galaxy. One of his methods was to drain the life force of other beings which he could do to entire planets, in order to prolong his life. He also could move his spirit into other body's. his original form was a tall pure blood with red skin under his birth name of Tenebrea, to rule the sith empire he adopted the body of a short stature human male with pale gray skin and yellow eyes under the name of Darth Vitiate. Once he abandoned the sith empire to form the Eternal Empire, he possessed the body of a high class noble under the name Valkorion and formed his new empire not in line with either the sith, nor jedi.