In The Lost Canvas, Dohko is portrayed as a young man of eighteen years, still in the early days of his destiny as the Libra Gold Saint. Chinese by birth and trained in the Lushan region, he is a warrior whose personality differs notably from the wise, aged master he is known to become in later eras. At this stage, Dohko displays an impulsive and occasionally rash temperament, a youthfulness that manifests as great passion and a tendency to act on his emotions. He holds his fellow Saints in the highest regard and can become fiercely angry when they are threatened, sometimes without pausing to consider the full consequences of his own actions in the heat of the moment.

Despite this fiery nature, he is not reckless without purpose. He is a responsible figure who takes his duties seriously, and his motivations are deeply rooted in protecting his friends and the goddess Athena. His role in the story is pivotal from the very beginning, as he is the one who discovers the young Tenma, the future Pegasus Saint. Sensing the boy's immense and pure cosmos, Dohko saves Tenma's life and becomes his mentor, bringing him to the Sanctuary to be trained. This creates a strong, brotherly bond between them, with Dohko acting as a guiding, if sometimes overprotective, figure in Tenma's life.

Dohko shares a profound and well-documented friendship with Aries Shion, a bond that stands out as one of the strongest among the Gold Saints. Together, they are a formidable pair, frequently undertaking missions and supporting one another. Dohko also maintains a good relationship with Taurus Aldebaran, often confiding in him and Shion. Throughout the Holy War against Hades, Dohko undergoes significant development. He demonstrates immense bravery and strategic thinking, such as when he confronts the god Hades alone to allow his friends to escape, an act that nearly costs him his life. He survives a grievous wound and later undertakes a critical mission to revive Athena's divine Cloth, facing down numerous powerful Specters in the process. His most intense personal conflict is with the Specter Bennu Kagaho, a battle that showcases his growing maturity. Rather than simply seeking to destroy his enemy, Dohko perceives Kagaho's inner pain and sorrow, and attempts to redeem him, demonstrating a deep compassion that defines his character.

By the war's end, Dohko has proven himself a hero of immense caliber. For his service, Athena bestows upon him the divine gift of Misopethamenos, a technique that drastically slows his aging process, reducing his heartbeats to only a hundred thousand per year. This grants him a longevity of over two hundred years, but with the heavy responsibility of becoming the guardian of the sealed souls of the Specters, a silent sentinel waiting for the next Holy War. As an eighteen-year-old Gold Saint, Dohko wields a formidable array of abilities rooted in his command of the Seventh Sense, allowing him to move and punch at the speed of light. His signature techniques are centered on the image of the dragon, a symbol of his training in Lushan. His ultimate attack is the Rozan Hyakuryu Ha, or Mount Lu One Hundred Dragons Force, which unleashes a torrent of one hundred energy dragons capable of obliterating his target. Another powerful technique is the Lushan Rising Dragon Force, which he used to devastating effect against Kagaho. Furthermore, as the Libra Saint, he is the keeper of the Libra Cloth, which contains six pairs of powerful weapons—swords, tonfas, lances, nunchaku, triple-section staffs, and shields. It is his solemn duty to judge when these formidable arms may be used by other Saints.