Genjo Sanzo is a central figure in his narrative, a Buddhist priest who deliberately subverts the typical expectations of his role. He is a young man of about twenty-three years, easily recognized by his golden hair, drooping violet eyes, and the red mark on his forehead. His appearance is often noted as handsome, but his sharp, often annoyed expression tends to overshadow his fine features. He stands at approximately 177 centimeters tall and carries himself with an air of irritated authority.

As a priest, Sanzo holds the prestigious title of the 31st of China, making him one of the highest-ranking monks in his world. However, he has no interest in pious devotion. Instead, he is a heavy drinker, a chain smoker, and an inveterate gambler. His most notable deviation from monastic life is his reliance on a firearm, specifically a Smith & Wesson revolver, which he uses with expert marksmanship. To complete his unorthodox arsenal, he also wields a paper fan, which he primarily uses to strike his companions when they exasperate him.

Sanzo was not born into his position. His birth name was Kouryuu, and he was an orphan set adrift in a river as an infant. He was rescued and raised by the previous Genjo Sanzo, a kind and powerful priest named Koumyou, who became a beloved father figure. Sanzo's life was shattered one rainy night when a gang of youkai attacked, seeking the powerful sutras Koumyou protected. Koumyou was killed defending his young ward, and one of the sacred scriptures was stolen. This traumatic event, which the rain constantly reminds him of, is the core driver of his journey. His primary motivation is to retrieve the stolen Seiten Sutra and to hunt down those responsible for his mentor's death.

His personality is a study in stark contrasts. On the surface, Sanzo is cynical, cruel, and brutally short-tempered, with a favorite catchphrase of "I'll kill you" that he often directs at his own allies. He is egotistical, haughty, and dismissive, frequently referring to his traveling companions as mere servants and refusing to show gratitude. This cold exterior is a defense mechanism, rooted in the traumatic loss of his master and a deep-seated fear of forming attachments, a principle he misapplies from the Buddhist precept of muichimotsu, or holding nothing.

Despite this, under his abrasive veneer lies a man of unwavering intensity, calm judgment, and surprising charisma. He possesses a strong, if hidden, sense of justice and is quick to act in defense of others, even as he grumbles about it. He deeply cares for the three youkai who travel with him, even though he would never admit it. This is most evident in his relationship with Son Goku, whom Sanzo freed from a five-hundred-year imprisonment atop Mount Gogyou. He acts as a reluctant but devoted guardian to Goku, taking on a parental role that he often finds annoying but never abandons.

His role in the story is that of the leader. He is tasked by the Goddess of Mercy with a mission to travel west to stop the "Minus Wave," a phenomenon driving youkai insane. While his companions are all powerful youkai, Sanzo is human, a fact that highlights his strength of will. He leads with a combination of brute force and clear-headed strategy, keeping his often-bickering group focused on their objective. His key relationships are with the three he assembled: the powerful and childlike Goku, the flirtatious half-youkai Sha Gojyo, and the calm and polite Cho Hakkai. Though he is most openly hostile to Gojyo and Goku's constant arguments, he has also shown mercy and forged deep bonds with them, offering them a chance to start a new life away from their traumatic pasts.

Over the course of his journey, Sanzo undergoes a subtle but significant development. He is forced to confront his own hypocrisy regarding muichimotsu, realizing he has used the concept to avoid emotional connection out of fear of loss. Through the constant presence and loyalty of his companions, he begins to reluctantly acknowledge the strength found in these bonds, even if he never puts it into words. He learns to trust them, and in turn, accepts his role not just as a weapon of revenge, but as a leader and a protector.

Sanzo's notable abilities are as unorthodox as his personality. While his physical strength and hand-to-hand combat skills are formidable for a human, his primary weapon is his revolver, which is specially modified to kill youkai and dispel evil spirits. His most powerful artifact is the Maten Sutra, one of the five founding scriptures of the universe, which he carries on his shoulder. By chanting a specific mantra, he can unleash the sutra's immense power to purify corrupt beings or unleash raw destructive force. However, he prefers to rely on his gun, keeping the sutra as a last resort. As the reincarnation of the heavenly being Konzen Douji, he also possesses latent god-like qualities, including heightened strength and speed, as well as a strong resistance to illusions and mind control, though using these abilities to their fullest exhausts him greatly.