The Sith Empire strikes blow after blow against a Republic reeling from the return of its ancient enemies, and the Jedi scramble to defend their holdings. But Imperial victory is far from certain.
Teneb Kel, a fiercely clever young man apprenticed as a Sith after a life of servitude and toil, is selected by his masters for a secret mission—a mission concerning the Emperor himself and a threat to the Dark Lord's thousand-year plan. Doomed if he fails, expendable if he succeeds, Teneb must unravel the schemes at work around him if he is to seize control of his destiny and alter the course of history.
The Sith apprentice Teneb Kel, after leading the Sith to victory on the planet Begeren in 3678 BBY, is recalled to Dromund Kaas to stand before the Dark Council. Kel is forced to fight his master Lord Calypho, who had committed transgressions against the Empire and the Dark Council, and Kel is then tasked with hunting down the Emperor's apprentice Exal Kressh. Along with his Abyssin slave Maggot, Kel follows the Emperor's instructions to search for Kressh in the Lenico system, but when he encounters Kressh, she easily defeats him and destroys the space station they are on before escaping. Kel makes it to his ship, but Maggot is forced to land the damaged craft on the desert world of Lenico IV. Still injured, Kel heads out to salvage the wreckage of the crashed station to repair his ship, but he collapses and is forced to make camp. Kel then experiences a Force vision of an armored figure named Darth Thanaton and Kressh, who explains how the Emperor seeks to create unknowing agents of his will across the galaxy.
Upon awakening, Kel is confronted by the Jedi Master Jerbhen Hulis, who is also seeking Kressh, and the two ally briefly to rescue the surviving colonists and salvage the parts Kel needs. The Sith assassin then pursues Kressh to Korriban, where Kressh has given the Republic inside information so that they will attack the planet and she can infiltrate the Sith Academy to destroy the machines the Emperor will use to create his "children." Kel and Kressh battle once again in the depths of the Academy, and Kel emerges victorious, but he kills Maggot after the Abyssin overhears their discussion of the Emperor's plans in order to keep them secret. When he returns to the Dark Council, Kel blackmails the Council into making him a Darth—Darth Thanaton—in exchange for the knowledge of the Emperor's children.
Blood of the Empire was the second arc in the Star Wars: The Old Republic comic series, and as it was developed far closer to the game's release date, its artwork and story elements resemble those of the game far more closely than Threat of Peace. Written by Alexander Freed and pencilled by Dave Ross, Blood of the Empire was released in three issues, all of which were published over several months in 2010. Seven pages would be released every other Friday on the game's official site for a total of 28 pages per issue. The three issues of the webcomic were later published as comic issue by Dark Horse in the months after the completion of the webcomic.
Blood of the Empire saw the debuts of the X-70B Phantom, Darth Marr, Darth Vowrawn, and a number of other characters who later appeared in The Old Republic. The concept of the Emperor's Children is a major plot point in Act III for the Jedi Consular, and Teneb Kel is a recurring antagonist as Darth Thanaton for the Sith Inquisitor. Blood of the Empire also saw the first visual depiction of the Sith Emperor, though some confusion arose from his appearance as a Human despite Drew Karpyshyn's statement that the Emperor was biologically a Sith Pureblood. This contradiction was later resolved with the introduction of the Emperor's Voice, the host body that the Emperor possessed to preserve his true form.