Commander Bosaal was the captain of a ship caught in the Void. He was from a Delta Quadrant species that possessed a bilateral ridge running vertically along the front of their heads to their chest. (VOY: "The Void")
He was encountered by the USS Voyager when that Federation starship was trapped within the Void in 2377. Bosaal had technology that could help both ships escape the Void.
However, when he saw Fantome aboard Voyager, he described him as vermin. Members of Fantome's species, who were native to the Void, had infested Bosaal's ship, causing engineering problems. After Voyager beamed Fantome's people off Bosaal's ship, Bosaal became an ally of Captain Janeway's and offered to help their ships escape the Void.
Voyager chief engineer B'Elanna Torres said she needed to build a polaron modulator to generate the energy to escape the Void. Bosaal produced one, but he was soon found to have stolen it from another Void-trapped ship after he killed its crew. In Janeway's belief that using the device would make her and the crew of Voyager accessories to murder, she threw Bosaal and his ill-gotten polaron modulator out of the alliance.
Bosaal and his ship later reappeared with Valen's and sought to destroy Voyager. However, they were both left behind in the Void when Voyager and its allies escaped. (VOY: "The Void")
Bosaal was played by Michael Shamus Wiles. The final draft of the script describes this species as "a formidable-looking new alien."