The King of Sparta who led the 300-man contingent at the Battle of Thermopylae during the Persian Wars. While some city-states chose to surrender, Sparta prepared to meet the Persian army head-on. King Leonidas personally selected 300 men to take a stand at Thermopylae. He possesses strength that stands out even among the elite Spartan soldiers. He excels in tactics and combat techniques and commands absolute trust from his comrades. By order of Xerxes, who feared Spartan prowess, he was eventually killed by a volley of arrows rather than in close-quarters combat.

The strongest heavy infantry of the ancient Greek polis, Sparta. Militaristic Society: A system was established to cultivate robust soldiers so that a small minority of citizens (about 10%) could control a vast majority of slaves. Education: At age seven, they entered facilities for grueling physical and mental training. Stealing, stealth, and survival skills were part of the curriculum. Heavy Infantry Tactics: They overwhelm enemies using a dense formation called the Phalanx. They form rows, absorbing enemy pressure from behind while protecting their own left side and the right side of the soldier next to them with their shields, attacking with spears. While 30 minutes is usually the limit, the resilient Spartan phalanx could endure long battles by rotating the front line. Conversely, they are slow and vulnerable to attacks from the flanks or rear. Equipment consists of a large shield, spear, and sword. While the phalanx is their strength, they are peerless even in individual combat. The 300-man unit consists entirely of men who have sons to succeed them—elite warriors who do not fear death. Even after Leonidas fell, they fought a desperate final stand to protect the King's body, using bare hands and teeth once their weapons broke.

A force of city-states gathered to stop the Persian invasion. They utilize tactics like the phalanx; while inferior to Spartan soldiers, they fight well against light infantry in narrow passes. Traitors within the alliance leaked information about a bypass route to the Persians, leading 6,000 of the approximately 7,000 troops to retreat. The remainder stayed with the Spartans, were outflanked, and died in battle.

The fourth King of the Persian Empire and son of Darius I. Carrying out the will of his father, who died after a failed expedition to Greece, he personally led a massive army to invade Greece. He crossed the straits, marched south through the Greek mainland, and confronted the Spartan forces at Thermopylae.

The elite infantry unit of Persia. Equipment: Spears, daggers, bows and arrows, shields, and scale armor resembling fish scales under their tunics. If a member of the Immortals fell, they were immediately replaced by a new soldier, keeping the unit's strength constant at 10,000. Thus, they were regarded as a 'unit that never dies'.

The 200,000 soldiers of Persia. Consisting mainly of light infantry, they use swords, bows, and spears. While they have cavalry, their mobility cannot be fully utilized in narrow passes, and they are weak against the phalanx. Their light equipment could not withstand the pressure of heavy infantry.