Bjorn

Bjorn was a human inhabitant of the colony planet Lindis, alongside his brother Sven. At some point, Bjorn became friends with the Tenth Doctor. On the instruction of Odin, he and the Doctor were captured by Lord Thorir, along with many other colonists, and taken to "Asgard" to be converted into Vikings.

After escaping, Bjorn and the Doctor spotted Sven, who had been converted into a Viking. When Bjorn tried to free his brother from the Viking control by ripping off the helmet that was sending him instructions the helmet malfunctioned, electrocuting and killing him.

Bjorn then pretended to have been converted, escorting the Doctor into Valhalla as a "prisoner". While the pair were eventually discovered, they successfully managed to discover the truth about Valhalla and put a stop to Odin's mind control. (COMIC: Space Vikings!)