Jubei'Thos was the leader of the Blackrock Orcs during the Third War and an antagonist in Warcraft III. He is a devoted follower of the Burning Legion who believes that the orcs are their chosen people and has become so corrupted that he is now a fel orc.
Jubei'Thos rejected Thrall's call to join his new Horde when it was formed. Sensing that the second coming of the Burning Legion was at hand, Jubei'Thos rallied the Blackrock Orcs to bring chaos to Lordaeron in preparation for the Legion's arrival. He had his Slave Master to capture humans in the town of Strahnbrad so their Blademaster could sacrifice them to their demon masters. Though the Slave Master was killed, the orcs had been able to capture villagers to be sacrificed. In response, Arthas and Uther raided the Blackrock village and killed the Blademaster.
Leading the orcs to the Alterac Mountains, Jubei'Thos had the Blackrock clan build a Demon Gate to communicate with the Burning Legion and the demon lord Archimonde. Jubei'Thos' plan was discovered by Kel'Thuzad, now reborn as a lich of the Scourge. Arthas and Kel'thuzad then led the Scourge to attack the Blackrock Orcs. Jubei'Thos died in the battle, along with many of his clanmates.