Goki, also known as Gouki, is a minor antagonist who appears early in the story of Yu Yu Hakusho. His background is that of a demon, specifically a spirit-devouring ogre, who escapes from the Spirit World to the Human World. Prior to this escape, he was a criminal with a significant record, having accumulated twelve previous convictions. He becomes part of a small group of demons, led by Hiei, that steals three powerful artifacts known as the Artifacts of Darkness from the Spirit World, with Goki taking possession of the Orb of Baast.

In terms of personality, Goki is portrayed as a violent, bloodthirsty, and selfish demon. He is driven almost entirely by his own base desires, with his primary motivation being the fulfillment of his insatiable hunger for human souls. He shows a particularly cruel preference for preying on children, stealing their souls to consume later, and he displays no remorse for these actions. Goki is also straightforward and blunt in his evil intentions, willing to fight anyone who interferes with his feeding. He initially shows skepticism towards his ally Kurama, indicating a lack of trust, and is only convinced to cooperate through brute force, suggesting he respects strength above all else.

Within the story, Goki serves as the first major antagonist that the protagonist Yusuke Urameshi must face in his new role as a Spirit Detective. His role is to establish the nature of Yusuke's mission and provide an early challenge. Posing as a large human man, he is discovered by Yusuke in a car junkyard, where he reveals his true form as a gigantic red demon with long black hair, five horns, and long nails on his hands and feet. The battle against Goki serves to demonstrate Yusuke's initial weakness, as his physical attacks are ineffective against the demon's rock-hard skin, forcing him to rely on his newly learned Spirit Gun technique, which he fires into Goki's open mouth to defeat him.

Regarding key relationships, Goki is a temporary and unwilling associate of the demons Hiei and Kurama. He works with them solely for personal gain, intending to use the Orb of Baast to collect souls more efficiently. He has no loyalty to the group, and his relationship with them is purely transactional. His only other significant relationship is with his opponent, Yusuke Urameshi, whom he underestimates and to whom he ultimately loses. Unlike Hiei and Kurama, who become recurring allies, Goki does not undergo any development, as he is defeated, has the artifact he stole retrieved, and plays no further part in the series. He is a static, one-dimensional character whose defeat serves as a stepping stone for the protagonist.

Goki possesses several notable abilities. His primary power is his monstrous physical strength, which allows him to easily overpower Yusuke in their first encounter. His skin is incredibly tough, described as being as hard as rock, making him resistant to conventional physical attacks. He also has the ability to steal the souls of living humans, which he then consumes. The stolen souls appear as small floating lights, and he uses the stolen Orb of Baast to trap them for later consumption. Finally, Goki can assume a human form to blend into society, appearing as a large man with shorter hair, a green shirt, blue jeans, and white shoes. This disguise allows him to hunt for victims without immediately revealing his demonic nature.