Vasor was a trapper who lived in the frozen wilderness on Marinus.
Vasor tried to take advantage of Ian Chesterton and Barbara Wright, who had come to Marinus looking for one of the keys to the Conscience of Marinus. He put meat in Ian's bag when he went to look for the key, hoping wolves would attack him. However, Ian returned with Altos. They overpowered Vasor, who had tried to attack Barbara, and had him lead them to the mountains.
There, he tried to strand them by destroying a bridge, but they escaped. They followed him home and were in turn followed by Ice Soldiers. They hid in Vasor's house but the soldiers stabbed Vasor through the wooden door, killing him. (TV: The Keys of Marinus)