According to Klingon mythology, Kortar (also Kotar) was the first Klingon. He and his mate destroyed the gods who created them, and as punishment, Kortar was condemned to ferry the souls of the dishonored to Gre'thor on the Barge of the Dead. (VOY: "Barge of the Dead")
B'Elanna Torres encountered him on the Barge of the Dead during a near death experience. Kortar called her a "mongrel child" and recalled all the times she almost got onto the Barge of the Dead before. When her mother Miral appears on the barge, he told Torres that her dishonor had condemned her mother.
Kortar encountered Torres again after she had The Doctor induce another near death experience in order to save her mother. She offered to take her mother's dishonor onto herself but Kortar knew of the plan to reawaken her. After Torres stated that she would die, Kortar sent her mother to Sto-vo-kor and took Torres to Gre'thor. (VOY: "Barge of the Dead")