The Kradin commandant
The Kradin are a race in the Delta Quadrant. They are engaged in a war with a race called the Vori, although it is not clear which side started the war, or indeed if either is native to the contested planet.
The Kradin are a large, humanoid race with muscular ridges around the face and teeth on all sides of their mouth. According to the Vori, they are "beasts" who are capable of a variety of atrocities including rape and genocide. However there is no direct evidence for this. In fact, when Lieutenant Commander Chakotay of the USS Voyager was kidnapped by the Vori, the Kradin aided in his rescue.
It is interesting to note that the Kradin claim that the Vori are the aggressors but again there is little evidence for this. (VOY: "Nemesis")
The image of an angry Kradin was among the disturbing thoughts that Tuvok imposed upon the Mari Guill during a mind meld. (VOY: "Random Thoughts").
A Kradin fighter was taking part in Tsunkatse matches aboard Penk's ship. (VOY: "Tsunkatse")