Trajis Lo-Tarik's species was a humanoid species native to the Delta Quadrant. Their planet resided on one side of an enormous Mutara class nebula in this quadrant. The exact location of this planet was unknown but it was located on the side of the nebula that faced the Alpha Quadrant. In 2374 no member of this species had ever succeeded in crossing this nebula and they had no idea of what lay on the other side. Whether or not any of them succeeded since is unknown.
This species had a natural physical immunity to the subnucleonic radiation emanated by the massive Mutara-class nebula encountered by the crew of the USS Voyager. Their technology, however, was susceptible to damage that was inflicted by this radiation.
The only known individual of this species, Trajis Lo-Tarik, was extremely sadistic and enjoyed tormenting others by playing psychological games. Whether this was indicative of the behavior of his entire species or if perhaps he had simply gone mad from loneliness is unknown. (VOY: "One")