Trajis Lo-Tarik was an alien trader who appeared to Seven of Nine during her isolation, later revealed to be a hallucination.
Trajis Lo-Tarik seemed to be an alien pilot who approached Voyager while it crossed a radiation-filled nebula, asking to trade for supplies. Seven of Nine, who had been running the ship nearly alone while the crew lay in stasis, brought him aboard. Ron Glass played the role.
In One, Trajis soon disappeared into the ship and appeared to work toward destroying it, taunting Seven about her loneliness. The Doctor revealed that there was no one else aboard and that Trajis was a product of her growing isolation. Seven's struggle with him became a struggle to accept her need for other people.