Princess Teruhi, the 17-year-old black-haired, blue-eyed daughter of Sō Sukekuni, head of the Sō clan ruling Tsushima Island, shoulders significant political responsibility during the Mongol invasion. Confronting arriving exiles, she commands them to defend the island, projecting confidence despite private fears of the overwhelming Mongol forces.

She transforms from a sheltered princess into an active military participant, fighting skillfully with a bow alongside defenders. Profound grief strikes her after her father and brother Umajirō die in battle, yet she persists in the resistance, retrieving their heads to perform burial rites, honoring family and tradition.

Teruhi extends her leadership beyond ceremonial duties, making strategic decisions like relocating forces to a silver mine for defense and coordinating night attacks. She occasionally displays traditionally feminine behaviors, such as attempting to kiss the exiled samurai Kuchii Jinzaburō while he sleeps, reacting with fierce intimidation when discovered. Her dynamic with Kuchii involves mutual reliance, tactical disagreements, and unspoken tension, though she maintains authority over him.

Her childhood servant Kano acts as both confidante and protector. During a Mongol assault, Kano tries to kill Teruhi to save her from capture, instead rendering her unconscious and hiding her before being captured herself, underscoring their deep bond. Teruhi’s lineage traces back to her great-grandfather, Emperor Antoku, linking her to imperial history.

Her resilience endures betrayals within the defense forces and crushing enemy superiority. She balances noble expectations with battlefield pragmatism, evolving from a figurehead into a committed combatant dedicated to Tsushima’s survival.