Hak, originally Son Hak, served as General and Chief of Kouka's Wind Tribe. War-orphaned at age two during conflict with Xing, General Son Mundok adopted him. Raised within the tribe, Hak forged deep bonds with its people, viewing Mundok as a grandfather. His childhood included regular visits to Hiryuu Castle, where a chance garden encounter sparked lifelong friendships with Princess Yona and Prince Soo-Won. Hak often acted as their protector. By thirteen, Hak showcased formidable combat prowess by defeating General Lee Geun-Tae. At fifteen, King Il appointed him Yona's exclusive bodyguard after Hak intervened against Kan Tae-Jun's harassment. Though initially resistant, he accepted the role. His martial skills earned him the feared moniker "Thunder Beast" across Kouka. By eighteen, he commanded Kouka's castle forces while remaining Wind Tribe Chief, standing among the kingdom's most accomplished young leaders. His personality blends fierce loyalty, sharp sarcasm, and unwavering protectiveness. Professionally, he maintains formality with Yona and Soo-Won, using their titles despite their shared history. Witnessing King Il's bravery cemented his devotion to the royal family. Privately, he holds deep romantic feelings for Yona, suppressing them out of respect for her initial affection for Soo-Won, instead expressing care through teasing and steadfast protection. He playfully bullies companions, dubbing Kija "White Snake" and Jae-Ha "Droopy Eyes". Soo-Won's coup, resulting in King Il's murder, shatters Hak's world. Falsely accused of regicide and Yona's kidnapping, he escapes with her to the Wind Tribe. Planning a fugitive life, he ultimately yields to Yona's persuasion, joining her quest to find the four dragon warriors. Soo-Won's betrayal wounds Hak more profoundly than Yona, fueling unresolved anger and grief over their fractured friendship. He views Soo-Won's actions as both a personal and political betrayal, remaining unable to forgive. Combat prowess defines Hak. A master of the guandao, he delivers powerful, swift strikes capable of clearing wide areas like fog. He also excels in swordsmanship, archery, and hand-to-hand combat, possessing extraordinary physical strength noted even by the dragon warriors. His endurance proves remarkable, surviving venomous snake bites through sheer will. Combined with acute situational awareness, these skills cement his reputation as Kouka's strongest warrior. Journeying with Yona prompts significant growth. Initially overprotective, he learns to respect her determination, supporting her archery and swordsmanship training. He gradually forges bonds with the four dragons—sharing candid talks with Jae-Ha—and Yoon, forming a found family. His loyalty extends to this group, though Yona's safety remains paramount. Lingering trauma from Soo-Won's betrayal persists, yet he draws inspiration from Yona and Jae-Ha's capacity to move beyond vengeance; his own path to forgiveness remains unresolved. Physically, Hak stands tall (188 cm) with a well-built frame, sharp blue eyes, and short, messy black hair. His standard attire features a sleeveless blue overcoat over a royal blue robe, secured by crisscrossed black ribbons for unimpeded movement. He wears black pants and dark brown boots with similar ribbon patterns. He carries a white cloth-wrapped guandao and conceals a lapis lazuli necklace gifted by Yona beneath his garments. When disguised, he occasionally wears a sled hat.