Moku-gyou is composed of two separate creatures: the actual king, and a bird-like creature on the king's head.
The king portion has a large yellow sphere as a body. Six hair-like tentacles come out of the top of the sphere. There is a large, orange mouth on the sphere, which serves as an entrance into Moku-gyou's stomach. On the base of the sphere is a smaller orange sphere with two arms. Several tentacles come out of the bottom of both spheres. On the sides of the large sphere are two large legs, although they cannot be seen in-game.
The bird portion is much smaller, and is perched on top of the king's head. It is an orange bird with a long, wavy, yellow neck. The head has a yellow beak and long yellow hairs. The body is an orange sphere which appears to have a face and green arms. The body and neck both have tentacles similar to those on the king.
The two portions of Moku-gyou have a symbiotic relationship– the bird eats the "vermin", such as Retsu, which Moku-gyou is allergic to.
Moku-gyou lives in the Tree of Life, Mingke-shu, in Ming-ken.
When the player is Tou, Moku-gyou gives them the mission to go find the names of each of the Zoh-gaeru family's members, and input them into the computer in the Computer Room of Tong-tah, Thi-eng, as well as Tou's own name.
When the player is Byou, they must pick up Retsu and feed it to Moku-gyou to gain access into his mouth. Inside of Moku-gyou's mouth, Moku-gyou asks Byou who the eyeball inside belonged to. When the player answers "Tou-gyou" they receive the eyeball.
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This article contains important plot details.
At the end of the game, Tou-gyou reveals that with the other three kings, Moku-gyou overthrew him, cut him up into eight pieces, and scattered the pieces throughout the land after they found out about the use of human souls.