OVA
Description
Gu-En is a character from the manga and anime series Akatsuki no Yona, appearing in the OVA episodes that adapt the original four dragon warriors' backstory. He is the first generation bearer of the power of the White Dragon, known as Hakuryuu, and stands as one of the four original dragon warriors who served the mythical King Hiryuu.

In terms of background, Gu-En lived during the era of King Hiryuu, centuries before the main story. He was among the first humans to receive the power of a dragon god, gaining immense strength in his right arm. After receiving this power, he became one of Hiryuu's most trusted guardians, sworn to protect the king and never betray him. At some point before becoming a dragon warrior, it is heavily implied that he was a seasoned soldier or veteran fighter due to his comfort and experience on the battlefield. After the death of King Hiryuu, conflicts continued to arise as humans sought to capture the dragon warriors for their powers. During one such incident, Gu-En and the green dragon warrior Shu-Ten successfully rescued the blue dragon warrior Abi from captors. Eventually, Gu-En and the other original dragons, with the exception of the yellow dragon Zeno, left Hiryuu Castle to live their own lives. He went on to establish what would later be known as the Earth Tribe, passing on his legacy before dying of old age.

Gu-En's personality is described as being reckless as a wild boar, a comparison made by Zeno himself. He is loud, aggressive, confident, and tenacious, possessing a gruff and forthright demeanor with no capacity for deception. He leads from the front in battle and is an enthusiastic brawler, appearing almost fearless in combat. Despite his roughness, he is deeply loyal and devoted to those he considers his comrades. He is notable for being the most formal and respectful toward King Hiryuu as a monarch, often bowing to him. Despite his brash nature, he is apparently good-natured and popular among his men, as well as successful with women. Later in life, he proved to be the most well-adjusted of the original dragons, settling down to found a village that was not maladjusted, marrying and having children.

His primary motivation is the protection of King Hiryuu and his fellow dragon warriors, whom he considers brothers. He is driven by a fierce loyalty that compels him to face any threat directly. Even after Hiryuu's death and the dissolution of their group, his motivation remains tied to his bonds with the others, particularly his promise to Zeno that he would wait for him no matter how long it took. He holds a strong belief in the bond they share as brothers connected by divine blood, trying to unify the often fractious group under that idea.

In the story's narrative, Gu-En serves as the original White Dragon, providing historical context for the present-day character Kija. His actions and personality establish the foundations of the Hakuryuu lineage and the Earth Tribe. His key role is shown in the flashbacks that explore Zeno's past, revealing the deep friendships and eventual tragedy of the original dragon warriors. He participates in the battles to defend Hiryuu's kingdom and later works to rescue Abi when captured.

Regarding key relationships, Gu-En shares a bond with King Hiryuu, whom he respects greatly. He views the other original dragons—Abi, Shu-Ten, and Zeno—as his brothers, though it took time for the others to come to see things from his point of view. He is particularly close to Zeno, showing a specific fondness for the youngest member of the group. Before the group separates, he makes Zeno promise to visit him one day, a promise he holds onto until his deathbed. He also maintains a working relationship with Abi and Shu-Ten, fighting alongside them to rescue Abi when necessary.

Gu-En's development traces a path from a reckless and battle-hardened warrior to a more settled, though still gruff, founder of a village and a family. The most significant arc in his development is his unwavering loyalty to the promise he made to Zeno. He spends the decades after the dragons separate waiting for Zeno to visit him, a hope he clings to even as he grows old. In his final moments, he calls out to Zeno, chiding him for being useless and making him wait too long before closing his eyes for the last time. This moment highlights that his enduring love for his brother was the defining feature of his long life.

Gu-En possesses the notable abilities of the original White Dragon. His primary power is the Dragon Claw, which manifests in his right hand. This claw can change size and has immense strength, said to be ten times that of a normal human hand, capable of tearing through anything and easily piercing the bodies of soldiers on the battlefield. He is also a competent fighter in his own right, with extensive experience in combat and swordsmanship prior to receiving his dragon powers. Like all dragon warriors, he can physically sense the presence of others with dragon blood, allowing him to locate and track them. Unlike his descendants, due to his peak physical condition and experience, using his powers does not seem to drain his stamina as heavily.