Yog was a Yridian, and the captain of a cargo freighter.

In 2370, he purchased magnesite ore from the Duras sisters in the Ufandi system, but before the transaction could be completed the USS Enterprise-D arrived. Commander Riker then contacted Yog and offered him one-half gram of Anjoran bio-mimetic gel for the five hundred kilograms of magnesite already aboard Yog's ship, which he accepted. (TNG: "Firstborn")