The film "300" is another good example of why every hero in the movies needs a antagonist to transcend them to another level of hero. King Leonidas declares war against the Persians but is not backed by any politicians from Sparta. The Epheros also denied his attempts to war which meant Leonidas would be committing crimes against Sparta if he fought. He decided to take 300 of his best men to hold off the invasion until other forces could gather and deploy. At first, many of the Spartan people disagreed with Leonidas's decisions and spoke out against him. The common belief was that surrendering would be the only option. It was not until the Persians landed that people realized they must fight. Surrounding countries started to gather their forces and send them to where the 300 were fighting. The Persian king Xerxes was the perfect antagonist for a character like Leonidas. Xerxes and his armies believed he was a god and that their armies would face little to no resistance. Once the fighting started they realized it would be much tougher then they had thought. Leonidas was trying to show by example that Greece could not simply roll over and accept defeat. His men were able to hold off the Persian armies for more then three days. This allowed for the Spartans and surrounding countries to send armies and Greece ended up winning the war because of the 300's sacrifice.
In a sense Leonidas needed Xerxes because he understood that some of his people would not understand the necessity of war. This would change when they become aware of Leonidas and the 300's sacrifice. Xerxes's army was also supposed to be unstoppable, and so Leonidas being able to defeat a portion of his army showed the Greeks that he Xerxes was not invincible. I believe Leonidas's choice to fight Xerxes was based on the belief that this would be enough to rally the countries to defend the homeland. He was correct in his belief and ended up saving thousands of Greeks.
