Thestriel Kymeri, who later assumed the name of Voidsister Spellweaver, was a Dathomirian Witch who lived during the Galactic Civil War.
Sometime following the Battle of Yavin in 0 ABY, she was a member of the Howling Crag Clan, which was headed by the clan mother Amaya Kymeri. During the outbreak of the blackwing virus, Thestriel Kymeri became infected along with many members of the clan, and in an attempt to contain the outbreak, the Galactic Empire killed most of the clan. However, Kymeri, along with two of her sisters, Naija Kymeri and Denkra Kymeri, formed the Sisters of the Void, used spells to fight off the contagion, and took on new names, Thestriel's being Voidsister Spellweaver. Gradually, they began to lose the battle, and eventually, the Force ghost of Amaya Kymeri sent a spacer to kill the three sisters.
Thestriel Kymeri appeared as a non-player character in the 2003 video game Star Wars Galaxies, a massively multiplayer online roleplaying game developed by Sony Online Entertainment and published by LucasArts, prior to its closure on December 15, 2011. Thestriel Kymeri was added to the game with the "Game Update 19," released on December 14, 2010.