Altos (The Keys of Marinus)

Altos was a young man sent by Arbitan to find the keys to the Conscience of Marinus. Instead he and his friend Eprim were enslaved in the city of Morphoton. After being freed, he accompanied the First Doctor and his companions in their search for the keys. He met Varos who tied him up in the forest and abandoned Sabetha and Susan in a cave.

He and Sabetha were romantically involved, which was exploited by the Voord, Yartek, who forced him to hand over one of the Conscience's keys. (DW: The Keys of Marinus)