Darth Caedus, born Jacen Solo, was a human male who became a Sith Lord and turned against his family and friends, betraying his former principles and leading the Galactic Alliance he once championed into a reign of terror as he attempted to bring order and stability to a fractured galaxy. The son of Han and Leia Organa Solo, Caedus was once a leading Jedi Knight who proved crucial in defeating the Yuuzhan Vong and protecting the galaxy during the Yuuzhan Vong War. It was Solo’s desire to protect the galaxy and his increasing willingness to accept any cost in that cause that facilitated his fall to the ways of the Sith, a trait that had similarly corrupted his grandfather, the Chosen One Anakin Skywalker, into Darth Vader.
Born in 9 ABY, Jacen Solo spent most of his early years as the target of various kidnapping plots and schemes against his famous parents. When he was thirteen, he and his twin sister Jaina began attending the Jedi Praxeum on Yavin 4, where their uncle Luke Skywalker taught them the ways of the Force. There he made several friends, among them the Hapan princess Tenel Ka Djo, to whom he became strongly attracted. While training, he and his friends defeated numerous plots against the New Republic and, in 24 ABY, he and his younger brother Anakin were apprenticed to Skywalker.
A philosopher who struggled with the idea of employing violence to fight violence, Solo entered a personal crisis with the outbreak of the Yuuzhan Vong War. He preferred to serve off the front lines, but felt obligated to volunteer for the strike team assembled to eliminate the voxyn queen at Myrkr. There, Anakin Solo was killed and Jacen Solo stepped up to lead the team, killing the queen and ending the voxyn threat before he was captured by the Yuuzhan Vong.
Solo spent nearly a year in captivity, during which he was tortured for weeks at a time. Solo struggled with his circumstances and with the teachings of his captor and mentor, Vergere. He slipped to the dark side before returning and embracing the idea of responding to the universe with unconditional, all-encompassing love. He escaped Yuuzhan Vong custody with Vergere, a former Jedi of the Old Republic, and rejoined the war effort. In the final battle of the war, Solo stormed Supreme Overlord Shimrra Jamaane‘s Citadel and defeated Onimi, who was mentally controlling the Supreme Overlord, while Solo himself experienced a moment of unity with the Force.
Afterward, he spent five years visiting and learning from various Force-using sects. During his time with the Mind Walkers, he experienced a vision of a dark figure ruling the galaxy and became determined to prevent its fulfillment. He returned to the New Jedi Order during the Dark Nest Crisis and, armed with a more ruthless philosophy of accepting various sacrifices in the name of the greater good, conspired to eliminate the Killiks to prevent another vision of galactic war and protect his infant daughter Allana, secretly conceived with Tenel Ka Djo. In 40 ABY, Solo agreed to become the apprentice of Lumiya after probing the future and finding that, if he did not do so, he would kill Luke Skywalker and the galaxy would be consumed by chaos.
He embarked on a year-long descent into the dark side, slowly turning against the Jedi and his family as he grew darker and more extreme. After seizing control of the Galactic Alliance, killing Mara Jade Skywalker, torturing his former apprentice Ben Skywalker, committing multiple atrocities, taking Tahiri Veila as his own apprentice, and ascending to Sith mastery as Darth Caedus, he was finally killed by his twin sister Jaina.