The Gumon were one of the races of Nibel. Dwelling within the depths of the Forlorn Ruins, they were a spider-like race who used their long limbs and agility to navigate the various perils of the forest. The Gumon were tasked with protecting the Element of Winds and were also great inventors, able to use the Spirit Tree's light within their machinery.
Ori's first encounter with a member of the Gumon is Gumo, who watches the beginning of the Spirit Guardian's journey from the edge of Swallow's Nest. The pair of them later meet in Gumo's Hideout after Ori is trapped there thanks to Gumo being corrupted by the forest's blinding. Ori's kindness redeems Gumo and allows them to rekindle the Element of Waters.
Later, when Ori arrives at the Forlorn Ruins, Sein is shocked to see that all of the Gumon are dead, frozen after the Element of Winds was lost from Kuro's actions. As they travel further into the Ruins, Gumo follows and mourns for his race. After overhearing Ori and Sein's vow to restore Nibel in memory of the Gumon, Gumo takes one of his race's inventions and travels back to Swallow's Nest to use it and revive Naru.
At the conclusion of Ori's journey, Gumo joins Naru in the nest, finding a new place to belong as the last of his kind.
- One of the Gumon's inventions, the Light Vessel, is required to pass through the various areas of the Forlorn Ruins. The Ruins themselves match the Gumon's ability to be agile, with many passages and chambers requiring the necessity of travelling up the walls or on the roof.