Nakahn

From Memory Alpha, the free Star Trek reference.

In 2373, Nakahn was one of the Mikhal Travelers encountered by the USS Voyager. He operated a refueling outpost near Tarkan space. Captain Kathryn Janeway visited him at the Mikhal outpost in order to obtain supplies and assistance in plotting a course for the Alpha Quadrant. He told Janeway about a monstrous, living asteroid that he encountered. Another Mikhal named Zahir told her that the asteroid in question was not a living being, but was rich in beryllium, which Nakahn wished to keep secret.

The Doctor's program malfunctioned because he overloaded his matrix with too many subroutines from historical figures, and he turned into an evil Hyde-like personality. He attacked Nakahn by dragging his hands into a fire. He then ordered Nakahn to get him a ship and safe passage off the planet. The Doctor also attacked Zahir, and Nakahn was suspected of the crime. Nakahn told Tuvok about the Doctor, enabling the Voyager crew to fix the malfunction. (VOY: "Darkling")

Nakahn was played by Stephen Davies.