Name – Sean
Species –Human
Planet – Earth
Temperament – tough
Appearances – The Underwater Menace

Sean was a shipwreck survivor who was captured and set to work in Atlantis' mines. A burly Irishman with a sense of humour as well as a sense of injustice, he thwarted his masters all he could. When he got the chance to escape, he did. He helped the Doctor defeat Professor Zaroff's insane scheme.