The God Beast, Banko (神獣盤古 Kamikemono Banko?) was a large Waitanhua flower that was hidden within the Main Temple in Hōrai. Upon the events transpiring in Hōrai, the Banko was forced to assimilate with the Tensen Zhu Jin in their attempt to complete the Rite of Just Consumption.
The Banko was giant in size and was made up of multiple assimilated humans that formed a stem to support a giant bud on top.
After Zhu Jin forced the Banko to fuse with them, the giant flower took on the form of Zhu Jin's head with plant vines and anthers protruding from it and the bud opened to unveil a flower bed with a replica of Zhu Jin's Yin body as a stigma.
Upon it being morning, the Banko's form further evolved where it developed a body with veins and flowers sprouted from holes layered around it, two pairs of breasts, and four arms. Strands of vines also started to freely hang from its body.
The Banko was meant to cultivate a greater quantity of Tan than the pit in Eishū, however, due to the humans being consumed by the Banko's overwhelming Tao, the flower constantly wilted away and needed a century to be reborn again. Similar to the Tensens, the Banko's Tao would be in a weakened state when experiencing nyctinasty during the night. The Banko also possessed all of the Five Elements.
Upon fusing with Zhu Jin, the Banko became somewhat sentient and was powerful enough to take over Hōrai as if the palace became its entire body. As a result, anything living within it undergone Arborification from either the Tan particles in the air, its roots, or the giant monsters created. Zhu Jin also used the Banko to create multiple copies of Lord Tensen from its five tandens and could have them transform partially in their Kishikai.
At some point, Rien used the humans that traveled to Kotaku to create the Banko in her laboratory in hoping that she could create more of the Tan elixir. However, due to its high demand of needing more high quality Tao to stay alive, Rien concluded that the Banko was not yet perfect. Over the years, Rien tried to keep the Banko from dying but is met with failure with each attempt and had to wait for centuries for it to bloom once more. Rien also discovered that the Tan from the Banko became to potent for even the Tensens to consume and its effects would disrupt the balance in their Tao. In order to have the flower remain alive and produce more of the needed perfected elixir, Rien developed a plan to turn the human race into Waitanhua flowers and have them connect with the Banko.
During the Edo period, upon the arrival of a troublesome group of humans, Rien encountered Aza Chōbē, whose Tao was looked at as being the key to completing her research, and presented to him the Banko. Once Rien was finished with her experimentations on him, she was finally able to create the Elixir of Life and was ready to put her true plan into motion. Shortly after, the humans invaded Hōrai to retrieve the elixir and escape the island, which resulted in the defeat of three members of Lord Tensen and Zhu Jin receiving critical damage to their body by Yamada Asaemon Shion. The Tensen later crawled their way to the Main Temple with the intention of merging themselves with the Banko despite the warning they were given by Rien. As a result, the Banko emerges out of the Main Temple with Zhu Jin fused and spreads its influence across Hōrai.
After noticing how the Banko's tandens were coming under attack by the humans, Zhu Jin created multiple clones of the members of Lord Tensen to protect them. Once morning came around, the Zhu Jin-fused Banko's form further evolved and tried to protect itself from Yamada Asaemon Jikka but was ultimately beheaded and temporarily put to rest after having its five tandens destroyed by the combined efforts of the humans. However, after being replenished by the sun, the Zhu Jin-fused Banko stood back up and have its tandens slowly regenerate. Using his vines to destroy the roots of the four tandens, Aza Chōbē successfully puts an end to the giant monster after having cut off its regeneration link to the tandens.
- The Banko bears reference to certain religious and mythological elements:
- The name "Banko" translates to "Pangu" (盤古) in Chinese. The Banko most likely refers to the Pangu, the first living being that has been said to be the creator of all in Chinese mythology.
- The fact that it feeds off of human lives to stay alive is akin to Jubokko, a yōkai tree in Japanese mythology that grows by feeding on human blood.
- Rien forbidding Zhu Jin's past consideration of consuming the Banko is akin to the story of the Tree of the knowledge of good and evil in Abrahamic religions, in which Adam and Eve, the first humans, ate the forbidden fruit produced by the tree despite being told otherwise.
- The Banko creating Tan to extend lives is similar to the special tree, the Ginsengfruit tree, of Immortal Zhenyuan in Journey to the West, which produces only 30 pieces of fruit every 9,000 years; the fruit is shaped like an infant less than three days old. A person who smells the fruit can extend his lifespan by 360 years, while a person who eats the fruit can live for another 47,000 years.
- Jikka compared the Zhu Jin-fused Banko to a Huā Pò (花魄) or a Kodama.
- Jigokuraku Chapter 61, page 16