Tantor was one of the top generals of the Alliance to Restore the Republic during the Galactic Civil War against the Galactic Empire. Shortly after the Battle of Hoth, Tantor attended a highly classified meeting of the Alliance leadership in a Rebel safe house on the planet Zastiga. At the meeting Chancellor Mon Mothma revealed that the Alliance had learned of a second Death Star being constructed by the Empire above the moon of Endor. During the second day of the meeting, Princess Leia Organa proposed that she lead a small group of operatives on a mission to the Corva sector in order to distract the Empire while the Alliance Fleet gathered for the coming Battle of Endor. General Crix Madine volunteered to protect Organa on the mission, but Admiral Gial Ackbar claimed that both Madine and Tantor would need to remain an help plan for a team of Rebel commandos to infiltrate Endor. Madine instead sent the commando Lokmarcha with Organa, who was successful in her mission, and allowed the fleet to gather and defeat the Empire at Endor.