Shin-ah serves as the current Seiryuu (Blue Dragon), one of the four Dragon Warriors bound by bloodline to the dragon deity. Born in a secluded village carrying the Blue Dragon's bloodline, his mother committed suicide immediately after his birth upon confirming his identity as the next Seiryuu. Consequently, the villagers denied him a name, forced him to wear a mask to conceal his eyes, and referred to him solely by his title. He was placed under the care of the previous Seiryuu, Ao, who raised him in isolation away from the village. Ao trained him in swordsmanship and warned him against using his dragon abilities, describing them as a curse that backfired on the user. Despite this isolation, Shin-ah and Ao protected the village from bandits and soldiers. At age four, after Ao lost his powers and died, Shin-ah faced a soldier attack alone. With no alternative, he used his dragon eyes to annihilate the soldiers but collapsed paralyzed from the power's backlash. This event intensified the villagers' fear, prompting them to relocate deeper into the Fire Tribe mountains and confine Shin-ah to a remote cave. He remained there for years in near-total darkness, his sole companion a squirrel he named Ao after his mentor. During this time, he attached bells to his mask, hoping their sound might lead someone to find him. Shin-ah possesses distinctive physical traits: pale skin, blue hair, and golden dragon eyes accented by red facial markings. He consistently wears a horned skull mask—originally with two bells on the left horn—and a detachable white fur piece covering his hair and neck. His standard attire includes a black robe with white fur trim over a blue turtleneck, fingerless gloves, and a sword strapped to his back. In crowded settings, he occasionally substitutes his mask with a white cloth to cover his eyes while minimizing attention. Years of isolation left Shin-ah with acute social anxiety and underdeveloped communication skills. He rarely speaks, relying on gestures, nods, or silent stares, which others often misinterpret as threatening or suspicious. Beneath this exterior, he exhibits profound kindness and empathy, even toward villagers who shunned him. He deeply fears his dragon powers, labeling them a "curse" due to their uncontrollable nature and self-destructive consequences. His powers comprise two primary abilities: extreme long-distance vision and a paralyzing gaze that induces fatal hallucinations or complete systemic shutdown in victims. Using this gaze risks him losing control to the dragon's murderous will and results in his own temporary paralysis afterward. To avoid reliance on this power, he honed exceptional swordsmanship and craftsmanship, creating weapons like bows and arrows from natural materials. His life shifted when Yona and her companions entered his village seeking his aid. After rescuing Yona from a villager's trap and guiding her to safety, she later approached him in his cave. He initially rejected her alliance request, citing his "cursed" status, but reconsidered after an earthquake trapped them together. When villagers panicked upon seeing his unmasked face, Yona defended him, empathized with his isolation, and vowed they would find freedom together. After their escape, he accepted her invitation to join her journey, bowing to the villagers in gratitude before leaving. Yona named him "Shin-ah," meaning "moonlight" in Kouka's language, a name he cherishes as symbolic of his new purpose. Within Yona's group, Shin-ah gradually developed trust and openness. He removed his mask around them, showing reduced fear of judgment. His loyalty manifests as fierce protectiveness, particularly toward Yona; he reacts with intense anger to threats against her, such as during the Water Tribe Nadai crisis where he nearly severed an assailant's arm for grabbing her. He also forged bonds with fellow dragon warriors: a brotherly dynamic with Kija, playful interactions with Zeno (who finds him "cute"), and cautious exchanges with Jae-ha, who teases him about his eyes. His pet squirrel Ao remains a constant companion. A pivotal development occurred when a prior Seiryuu possessed him in the "Forest Lushing Blue" arc, granting him full control over his dragon eyes. Despite this mastery, he continues wearing his mask or eye coverings out of lingering discomfort without them. He also demonstrated personal growth by forgiving his village for their mistreatment, reflecting his resilience and lack of bitterness. At 18 years old, Shin-ah is the youngest among the current dragon warriors. He harbors a pronounced dislike for cold weather, often using his fur piece for warmth, and exhibits a substantial appetite, possibly stemming from survival habits during his cave-bound years.