Semage was a member of the human species, working as a guard for the Galactic Republic's Senator Larik. He and another guard, Hanel, sought to compel the dishonest Larik to go to Raxus Secundus, but their plan was thwarted by Dooku and Mace Windu following the murder of a Jedi on that planet. Semage and Hanel attempted to kill the two Jedi Knights, but they were ultimately defeated. Semage was taken into custody by the two Jedi, while Hanel perished during the subsequent conflict. Semage was incarcerated alongside the other plotters, where Dooku came to see them, advising them to maintain their resolve for the struggle ahead.