Hien is a Midlander Hyur with messy black hair tied back in a topknot with red and orange ribbons and a beard trimmed to his jawline. He wears a yellow fur-trimmed robe with misty mountain designs and light armor. Being a Doman samurai, Hien carries a katana with an ornate design.
Hien harbors a deep sense of honor and duty to his country and initially feels great remorse for the fall of his kingdom. He believes if his people are content under Garlean rule, he would not force them into revolting just to put himself on the throne. He carries a friendly and competitive attitude among his peers. He is a capable leader and puts the safety of his people above his own status.
Despite his great wisdom and serious nature when in battle, Hien possess a healthy sense of humor when with friends and trusted comrades.
Hien decides to destroy Doma Castle if it means ending the siege sooner with less bloodshed. He occasionally clashes with his trusted companion, Gosetsu Everfall, over the subject of tradition (the latter objects the destruction of Doma Castle due to its historical significance), but Hien believes one should not be weighed down by the past when forging a new future.
Hien is has been hiding at the Azim Steppe since the defeat of the Doman resistance. When approached about returning to lead the Domans, he agrees if his people wish to continue the fight, not wanting them to suffer the empire's wrath unwillingly. After being shown their desire to try once more to overthrow the imperial occupation, Hien agrees to return, though he first needs to gather an army, planning to create one from the many Xaela tribes that populate the Azim Steppe.
Hien allies with the Mol Tribe, and agrees to lead them to victory in the upcoming Naadam, the ceremonial battle that determines the leadership of the Steppe. Along with the Warrior of Light, Gosetsu and Lyse, he meets with the leaders of several of the other Au Ra tribes and completes the trial at Bardam's Mettle before winning the Naadam for the Mol. Once the tribes unite under his leadership during the fight against the empire, Hien returns to Doma to prepare for the upcoming battle.
He supports Alphinaud's plan to defeat the imperial occupation, but later modifies it to include the flooding of Doma Castle. Although destroying the castle would be a great loss to his country, doing so would mitigate casualties among his people, which he sees as far more important. The plan succeeds, and the Garlean forces are driven out. As the Scions of the Seventh Dawn prepare to return to Eorzea, Hien thanks them for helping liberate his country, and promises to return the favor by helping them in the upcoming battle to defeat the imperial forces at Ala Mhigo.
Hien is true to his word and leads the Xaela tribes to provide crucial air support to the Eorzean Alliance at the final siege of Ala Mhigo, and he helps fight off imperial soldiers outside the throne room. Hien is present when Zenos yae Galvus is defeated and Ala Mhigo celebrates its long-desired freedom.
Following Ala Mhigo and Doma's liberation from the Garlean Empire, Hien makes efforts to rebuild his homeland. Gosetsu is revealed to be alive and taking care of an amnesiac Yotsuyu, and though Hien understands that the world had been cruel to the woman, he believes it does not excuse her crimes against Doma. Gosetsu convinces him to spare Yotsuyu due to her having no knowledge of her sins. Hien is ultimately forced to reveal that Yotsuyu is alive to his people after she runs off to fetch a piece of fruit for Gosetsu. Though the people remain fearful of her and cry for her punishment, Hien restrains them and assures she will not be allowed to leave his den unescorted.
Hien is visited by a Garlean transport with a Doma signal of negotiation and Hien and his friends meet Asahi sas Brutus and the members of the Popularas. Further surprising Hien and the Scions, Asahi comes with word from Emperor Varis that the empire is open to peace negotiations. Skeptical of their intentions, Hien nonetheless hears their story. The empire is willing to recognize Doma's newly gained freedom as a nation if they outlaw summoning and wish to conduct a prisoner exchange: conscripted Doman citizens for the acting viceroy Yotsuyu. Hien refrains from answering, wishing to confer with his advisers and friends.
Asahi was merely acting on behalf of a "resurrected" Zenos, who conspires to undermine Varis's motion of peace with Doma. Asahi probes Yotsuyu into reverting to her sadistic self and gives her the means to summon a primal within herself, making her violate the terms of their negotiations of peace, threatening to spark new conflict with the empire and pin the blame on Doma. The Warrior of Light defeats the primal form of Yotsuyu and confronts Asahi who reveals everything during his rant, which his second-in-command, Maxima, overhears. Yotsuyu, with the last of her life, kills Asahi, finally achieving her vengeance.
With the struggle over for now, Hien and the Scions meet with Maxima who, in Asahi's stead, completes the prisoner exchange, preserving the fragile peace. Wishing to learn more about the newly returned Zenos, Hien allows Alphinaud to travel with Maxima to Garlemald to conduct an investigation, however, they never hear back from him.
Feeling responsible, Hien travels with the Scions in search for him. A clue and the last message from Alphinaud takes them to the wasteland of The Burn. They find the wreckage of Alphinaud's transport and the remains of their attackers, soldiers of the imperial family's personal guard. They conclude that someone in Garlemald ordered the attack.
Back in Doma, Hien meets with Lyse who serves as a representative of the Eorzean Alliance. She informs the Scions and Hien that the liberated Ala Mhigo has agreed to join the Alliance and calls for a meeting with Hien invited. Hien agrees but first takes priority to fortify his homeland's defenses in the wake of a possible Garlean invasion. Gathering friends and allies, Hien concludes that Doma cannot repel a full force invasion, as the country does not possess the resources and people necessary for such a defense. Realizing that no single nation can defeat the empire, Hien announces he intends to follow the example of his Eorzean friends by forging an alliance with Doma's eastern neighbors. Hien hopes that by reaching out to Hingashi, Sui-no-Sato and even to the conquered provinces of Dalmasca and Nagxia they can pressure the empire to avoid fighting on two separate fronts. Though Hien knows not all will answer the call, he is confidant that Doma's neighbors all harbor the same desire for freedom, and if made aware of what is at stake, they may agree to an alliance.
Hien (飛燕?) means "flying swallow" in Japanese.
The former Doman king, Kaien, his wife, Mina, and the prince, Hien, allude to Cyan Garamonde and his wife and son Elayne and Owain from Final Fantasy VI. Kaien's name is based on the romaji of Cyan's Japanese name, Cayenne (カイエン?), Mina's name is the same as Elayne's Japanese name, Mina (ミナ?), while Hien's childhood name, Shun, is based on Owaine's Japanese name, Shun (シュン?).
- The party finds Hien on a cliff similar to how Cyan is found in the World of Ruin in Final Fantasy VI.
- Hien's childhood name, Shun, was given to him by his mother and he gets embarrassed whenever he is addressed as such.
- Of the leaders of the free world who resist the Garlean Empire, Hien is the only one who is part of a monarchy, having succeeded his father as leader and liberating his homeland of Doma.
- Ishgard formed a republic following the abolishment of the theocracy with Aymeric de Borel becoming the elected Speaker of the House of Lords, and thereby the leader of his nation.
- Nanamo Ul Namo is nominally the sultana of Ul'dah, but she is beholden to the Syndicate council and plans to turn Ul'dah into a republic.
- Gridania is ruled by a council of Seedseers, though Kan-E-Senna is the de facto leader of her nation.
- Limsa Lominsa is a thalassocracy where sea captains prove themselves in a competition with Merlwyb Bloefhiswyn serving as the leading admiral.
- Recently liberated Ala Mhigo has yet to establish a government but intends to form one modeled after Ishgard's House of Commons.