Trisdin Gheer served as a retainer for Ta'a Chume during the Yuuzhan Vong invasion and was also affiliated with the Ni'Korish faction.
Despite outward appearances suggesting complete allegiance to Ta'a Chume, Trisdin was secretly acting as a double agent, gathering information for Ta'a Chume's niece, Alyssia. Following the conquest of Coruscant, when Teneniel Djo, the Dathomirian daughter-in-law of the Queen, initiated the process of welcoming refugees into the Hapes Cluster, Trisdin proposed to Ta'a Chume that they find and prepare a young woman to take Teneniel Djo's place as the spouse of her son, Isolder. Ta'a Chume and Trisdin devised numerous schemes, which included assassinating Teneniel Djo and preparing Jaina Solo to eventually ascend to the position of Queen Mother. While they successfully carried out the murder of Teneniel Djo, their attempt to install Jaina as her replacement ultimately failed. Trisdin met his demise when Jaina tricked him into freeing the pirate, Crimpler, who then killed him before fleeing from imprisonment.