10 Most Shocking Betrayals In Movie History

9. Ephialtes - 300

In this 2006 adaptation of Frank Miller's historically inspired comic-book series, King Leonidas of Sparta and his army of 300 go on a jolly romp around Greece, slaying Persians in typical Zack Snyder super slow motion. It is in the early stages of their defiant last stand at Thermopylae that Leonidas comes across the path of Ephialtes, the severely deformed son of a Spartan exile who wishes to fight alongside the 300 in order to redeem his Father's name.

Unfortunately, and to Ephialtes' dismay, Leonidas can only offer him the duties of clearing corpses from the battlefield and fetching water for the men, as Ephialtes' deformities prohibit him from fighting like a Spartan. Ephialtes turns on the Spartans when offered various luxuries by King Xerxes of Persia. Ephialtes tells Xerxes of a flanking route that his forces can use to surround the Spartan warriors, thus dooming the 300 to outright slaughter.

This betrayal is the pivotal moment in the film, and it's made significantly worse by the fact that it's at the hands of a man who chose Persian luxury over Spartan honour.