|Appeared in:||Sinbad: Legend Of The Seven Seas|
He and Sinbad were at first friends until Sinbad found out that Proteus was to marry Marina before the movie. Sinbad, in love with Marina, or at the very least her beauty, then ran away and the two haven't seen each other since, until the beginning of the movie. The absence caused a sort of rivalry, making Sinbad a bit bitter and intentionally unwilling to go back to Proteus's country. Proteus was unaware of the reasons of Sinbad's absence and eventually his prince duties also set the two friends apart even before Sinbad left.
It was planned that Proteus was to marry Marina until he volunteered himself for execution in Sinbad's place. She then snuck away to Sinbad's ship to make sure that Sinbad would bring the Book back and save him. Marina's feelings changed, and Proteus did not hold it against her. He encouraged her to follow her dreams and let her return to Sinbad and break the engagement. At the very least, Proteus was fond of Marina.