Sapan was a lama at Det-Sen Monastery. When Khrisong tied the Second Doctor to the monastery gate, Sapan wanted him to consult the Abbot first.
He and Rinchen made a spirit trap around the captured robot Yeti. When the monks were forced out of the monastery by the threat of the Great Intelligence, Sapan took charge of Songsten, who was disorientated after being hypnotised. (TV: The Abominable Snowmen)