A Yridian trader questioned by the Enterprise-D in 2370 over magnesite ore taken from a mine linked to the Duras sisters.
Yog is a Yridian who appears in the episode Firstborn, played by Joel Swetow.
After an attempt on the lives of Worf and his son Alexander is blamed on the House of Duras, Riker goes looking for Lursa and B'Etor. A tip from Quark on Deep Space 9 points to a mining claim the sisters have been working in secret. The trail of the ore leads to Yog's freighter.
Yog denies having anything to hide. Riker shows that his cargo contains magnesite from the sisters' mine and threatens to take the lot, and the Yridian becomes helpful. What he says allows the Enterprise to find the sisters' Bird-of-Prey. When they are confronted, Lursa and B'Etor turn out to have had no part in the attack, which was arranged by the visitor K'mtar.