Born in the minor city of Astakos, Xeones is orphaned at age ten when his home is sacked. He is a resilient survivor who eventually travels to Sparta, hoping to learn martial skills to prevent ever being victimized again. Because childhood injuries to his hands prevent him from gripping a heavy shield, he serves as a squire and archer rather than a frontline fighter. He is intensely loyal and consistently chooses to remain with his Spartan masters out of devotion rather than obligation.

A youth of the Spartan nobility currently enrolled in the agoge military training program. Alexandros is renowned for his physical beauty and exceptional singing voice, but he suffers from asthma and a slight build that make it difficult for him to keep pace with his peers. He possesses a tender heart but is fiercely determined to prove his bravery and overcome his reputation as a physical weakling.

A highly respected veteran of the Spartan army who prefers serving as a platoon commander rather than seeking individual glory in the royal guard. Dienekes is introspective, philosophical, and physically unassuming, bearing an old ankle wound and a large scar on his forehead. He constantly analyzes the nature of courage, concluding that true bravery stems from love for one's comrades rather than an absence of fear.

The tall, beautiful, and regal wife of Dienekes. Arete possesses exceptional intelligence and a commanding presence that allows her to navigate the male-dominated sphere of Spartan politics. She embodies the profound courage expected of Spartan women, bearing the immense emotional burden of supporting a nation of warriors while quietly grieving her family's losses.

A physically imposing helot (Spartan slave) who seethes with resentment over his subjugated status. Because he is the illegitimate son of a famous Spartan citizen, he believes he is entitled to full citizenship. He frequently rejects offers of partial status, demanding full recognition, and openly expresses a desire for the downfall of the Spartan system that oppresses him.

The senior king of Sparta, nearing sixty years old but still fighting on the front lines. Leonidas leads strictly by example, refusing to exempt himself from the brutal training or menial labor expected of his soldiers. He is a pragmatic tactician and a brilliant orator whose speeches bind the disparate Greek allies together in the face of overwhelming odds.

The Emperor of Persia, determined to fulfill his deceased father's ambition of conquering the Greek city-states. Xerxes is mercurial and commands a staggering number of conscripted soldiers. He observes battles from a safe distance on a royal platform, contrasting sharply with the frontline leadership of the Spartan kings.

Regarded as the finest single warrior in Greece, Polynikes is a two-time Olympic victor known for his flawless physique and lethal combat skills. He is arrogant, condescending, and driven by a thirst for personal glory rather than community duty. He frequently bullies those he considers weak, particularly young Alexandros.

A blind slave belonging to Xeones's family in Astakos. Having been captured in a war decades earlier and branded on his forehead, Bruxieus possesses deep knowledge of the natural world. He guides Xeones and Diomache through the wilderness, teaching them survival skills and imparting crucial lessons about civic duty and courage.

Xeones's confident cousin, two years his senior. After surviving the sack of their city, she endures severe trauma but remains focused on reintegrating into civilized life. She eventually separates from Xeones to travel to Athens, seeking a husband and a return to normalcy. She channels her grief into profound compassion for others.

The polemarch, or battle-leader, of the Spartan army. Olympieus is one of the oldest and most distinguished warriors in the city, serving as a vital strategic advisor to King Leonidas. He embodies traditional Spartan nobility and commands immense respect from his peers.

The captain of the Ten Thousand Immortals, the elite household guard of the Persian Emperor. Unlike many of his arrogant superiors, Orontes is fair-minded, generous, and genuinely curious about the Greek defenders. He develops a sincere respect for Xeones during the prisoner's convalescence.

The official historian and scribe attached to Xerxes's military campaign. Tasked with extracting intelligence from Xeones, Gobartes meticulously records the prisoner's story. Through these interviews, the scribe develops a profound appreciation for the Spartan way of life and a personal affection for Xeones.

The devoted wife of Olympieus and mother of Alexandros. Paraleia represents the intense, quiet courage required of Spartan women. She constantly worries about her son's physical limitations but must maintain a stoic public facade, subordinating her personal maternal grief to the needs of the city.

The wife of King Leonidas. Gorgo embodies the highest ideals of Spartan womanhood, bearing the heavy emotional yoke of leadership. She serves as a pillar of strength for the other wives, advising them to hide their grief to endow their men with courage.

A merchant from the Greek colonies in Asia Minor. Elephantinos is cheerful and affable, endearing himself to the Spartan soldiers with his oddly accented Greek and warm humor. He serves as an informal morale booster, bringing comfort and jokes to the frightened allied soldiers.

The captain of the Thespaian troops allied with the Spartans. Though he lacks the lifelong martial upbringing of the Spartan commanders, Dithyrambos proves to be a highly capable leader and a ferocious fighter who earns the respect of his legendary allies.

An impeccably polite, strikingly handsome captain of the Egyptian marines in the Persian fleet. The Greeks nickname him "Tommie" due to his unpronounceable real name. He frequently serves as an emissary, smoothly urging the Greeks to accept vassalage under Xerxes in exchange for favorable treatment.

An old Scythian warrior exiled from his homeland for murder. He arrived in Sparta begging to be killed, which earned him his bleak nickname. He serves as a loyal squire and fights in a frothing, berserker rage using cut-down javelins he calls his "darning needles."

Xerxes's senior military commander. Mardonius is proud, vain, and consistently dismissive of the Greek defenders. He dislikes receiving intelligence that contradicts his assumptions and heavily relies on the sheer size of the Persian army to guarantee victory.

Dienekes's deceased older brother. Iatrokles was an Olympic champion who achieved legendary renown before his early death in battle. His memory heavily influences the lives of his surviving family members.

A famous Spartan warrior who passed away before the events of the main narrative. He is remembered for his bravery and physical strength, traits he passed down to his illegitimate offspring.

A harsh survivor who leads a band of orphaned youths following the destruction of Astakos. He attempts to recruit Xeones into his gang early on, and years later, he operates as a local outlaw who assists the Spartan forces by serving as a scout.