Kizu Katayama, also known as Darth Obsion, was a human, male Dark Jedi who served in different orders and with changing affiliations, most notably with the Sith Ancients and the Dark Ancients. He recruited Salem Benedict for the Sith Ancients and formed a close relationship with her. They both shared an unnatural resistance to the corruption of the Dark Side.
Little is known about the past of Kizu Katayama. He was found near a waste outlet next to a genetic engineering facility on Kashyyyk by his first Master, a Jedi known as Master Maraketh who taught Kizu the ancient ways of the Jedi and raised him to follow them. One day, when Kizu was gathering supplies from a local trade station a Sith attack occured during which his Master was killed and their home destroyed. This attack was lead by Darth Adazca who took the young Kizu with him to teach him the Dark Side of the Force.
Training under Darth Adazca
After extensive training under Darth Adazca the Sith realized that Kizu showed an unnatural resistance to the corruption of the Dark Side. As further attempts to corrupt him failed he was labeled a Dark Jedi and sentenced to death. Kizu however managed to escape the Sithlords evil grip just in time.
Dark Jedi in Exile
While being exiled, Kizu thought of ways to seek revenge against his former Master Adazca. He didn't plan to kill him, but instead planned to teach him a lesson. The opportunity arose when Adazca sent his other apprentice, Salem Benedict, to kill Kizu. Salem was at the brink of being granted the title of Dark Lady, as her teachings were almost complete; yet in order to reach the prestigious rank she had to hunt down Kizu to end his life by the order of Darth Adazca. The two fought excessively and Salem almost would have killed Kizu, yet in a surprising move, he was able to overcome her. After the fight the exhausted Kizu chose to use his newly acquired healing-powers to safe Salem's life and revive her. Salem, faced with her defeat, chose to return to her Master, knowing that her failure would result in her own death by Adazca's hand. Kizu however, strengthened by his victory, chose to follow Salem in order to challenge Adazca.
The Victory over Darth Adazca
Upon his return, Kizu would find Salem at Adazca's feet about to be killed. Adazca however couldn't overcome his affection for Salem, therefor failing his own Order's rule. He commanded his other Apprentice, Archer Field, to kill Salem. It was at this point that Kizu intervened and challenged Adazca to duel him. Weakened by his realization Adazca was still able to counter Kizu's challenge but due to his inability to kill Salem he was delegitimized as the Order's leader and was defeated in a combined effort of Darth Dawndeath, Lord Escape, Salem Benedict and Kizu himself. After being victorious in the duel Kizu and the others had managed to completely humiliate Adazca by refusing to grant him an honorable death during the duel. Adazca, shamed and agonized, went into exile, turning his back to his order. The Sith Ancients were taken over by Lord Escape and Salem became Kizu's apprentice.