After the Minotaur escapes from the Labyrinth, he helps Hercules face it. Theseus has a double identity, his second self being the superhero "Grim Avenger", whose costume resembles that of DC Comics' character Doctor Fate, though his personality and back story are more inspired by Batman. As the Grim Avenger, Theseus is constantly narrating his every move aloud. He was once one of Phil's former students as well as mentioned in the movie.
In the original myths Theseus was the son of Poseidon and Aethra, wife of Aegeus King of Attica.
It is unknown if Theseus was later killed by the Minotaur.