|Alias||Thunder Beast of Kouka|
|Previous Occupation||King's 4 Great General|
|Previous Affiliation||Royal Palace|
|Relatives||Son Mundok (adoptive father); Tae-Yeon (adopted little brother)|
Hak, or Son Hak (ソン・ハク Son Haku) as he was known at the beginning of the story, is an adopted child of Son Mundok of the Wind Tribe. He starts off the story as the Wind Tribe General, as well as Yona's wise-cracking childhood friend and bodyguard who happens to be in love with her. He is very strong, known to people to be the "Thunder Beast of Kouka". When Soo-Won kills Emperor IL, Hak takes Yona and escapes from Hiryuu Palace.
Hak is a tall, well-built man with black hair and blue eyes. His main outfit is blue and grey with a dark blue overcoat. He carries around his signature weapon on his back or over his shoulders.
In flashbacks, it becomes known that Hak, Yona, and Soo-Won had all become childhood friends at one point, though the exact age this was at is unknown (perhaps age 13 for Hak and age 11 for Yona, as illustrated by the author). However, by the age of 15, it is clear that Hak is in love with Yona, who surprisingly is mature enough to recognize his own feelings at this time. In turn, Hak also knows that Yona is in love with Soo-Won, which irritates him.
During this period in their lives, Hak officially became Yona's bodyguard when he defends Yona from the Fire General's son, Kang Tae-Jun, and his advances. By the age of 18, Hak had already reached the status of Commander of the castle guards and earned the title of "Thunder Beast" or 'raijuu'. Added to this list of titles is 'Chief of the Wind Tribe', making him one very young and accomplished person.
Hak's spear fighting skills are the best in the country. His speed and strength allow for powerful blows to be dealt, even strong enough to sweep aside a large area of fog with one swift strike. Kija once observed that his strength could be on par with his own power. Even without his weapon, he can deal strong blows with his fists.
Hak is also very knowledgable of the areas in the land of the tribes, being a general of the Royal Family, and has been proven useful during their journey in finding the four Dragons. He is also skilled in swordsmanship and archery, in addition to the spear.
One of his more defining attributes is his stalwart heartiness, first shown when enduring a bite from a poisonous snake when protecting Princess Yuna. That being said, this may be mostly due to his determination to live and protect Yuna, both out of loyalty to the King and the Princess, as well as love.
- In the planning phase of Akatsuki no Yona, Hak’s original name was “Soron”. It seemed too similar to “Soo-won”, so it was changed to “Hak-jin”. In the end, it was shortened to “Hak”.