Tosin was a Kolaati trader who dealt in illegal substances near the Nekrit Expanse. In 2373, after a prior deal with Wixiban and Neelix had failed, Tosin agreed to spare their lives only if they delivered three grams of warp plasma. Several people were injured and one killed when one of Tosin's men fired his weapon, igniting the warp plasma. One of Tosin's party was killed, the others taken into custody by Bahrat soon after. (VOY: "Fair Trade")

Tosin was played by Trek regular James Horan.
One of the group of three in which Tosin was said to be killed, but it was not specified who.