In Percy Jackson: Sea of Monsters, Percy’s cyclops half-brother is Tyson.
Tyson is the son of Poseidon and therefore shares a divine parent with Percy Jackson. The film presents him as a friendly cyclops who joins Percy and his companions during their quest to find the Golden Fleece. Douglas Smith played Tyson in the 2013 movie.
The film is based on Rick Riordan’s 2006 novel The Sea of Monsters, the second book in the Percy Jackson & the Olympians series. The movie combines Greek mythology with a modern adventure setting, but its characters and plot are separate from the ancient Pandora myth.
Tyson is sometimes confused with other young demigod characters in the franchise, especially Grover Underwood and Nico di Angelo. Unlike Tyson, Grover is a satyr and Nico is a son of Hades. Tyson’s defining mythological feature is his one eye and cyclops heritage.