Ulgo, who proclaimed himself King Ulgo the Magnificent, was a male Dulok hailing from the forest moon of Endor. His dwelling was a cave situated near the Canyons of Mist. It was there that a party of Ewoks from Bright Tree Village encountered him, having been deceived by Vulgarr, another Dulok, into believing a monster resided in Ulgo's abode. When the Ewoks liberated some lantern birds that Ulgo intended to consume, he launched an assault, only to meet his death during the resulting scuffle.
On the forest moon of Endor, the planet that served as the homeworld for his species, lived a male Dulok named Ulgo. Despite his claim to be king of all Duloks, he lived a solitary life in a cave near the Canyons of Mist, perched high upon the canyon walls close to the Whispering River. He would set traps using stranglevine to ensnare lantern birds, which he then used for both sustenance and illumination within his shadowy cave. At one point, Ulgo engaged in trade with Vulgarr, another Dulok who also asserted kingship, exchanging a pair of lantern birds for a vest crafted from the fur of Ewoks, another sentient species native to the moon. Vulgarr later plotted to abduct the Woklings from the Ewok settlement of Bright Tree Village, and to divert the village's warriors, he first captured a single wokling named Malani. Vulgarr then visited the Ewoks, falsely claiming that a monstrous creature had seized the child and directing them to Ulgo's dwelling, which he declared to be the monster's lair.
The warriors from Bright Tree Village, guided by gliders, followed the Whispering River to Ulgo's residence. There, Ulgo confronted them, demanding they vacate his territory. Chief Chirpa, the warriors' leader, explained that Vulgarr had deceived them. In response, Ulgo proudly displayed the Ewok fur vest he had acquired from the other king. This angered the Ewoks, particularly the warrior Pondo, who attempted to attack the Dulok but was restrained by his companions. Ulgo reacted to the attempted assault by threatening the Ewoks, who then prepared to leave.
Before their departure, however, Warok, the father of Malani, seized the caged lantern birds Ulgo was carrying and declared that the creatures were servants of the Great Spirit of the forest and must be freed. Infuriated by the loss of his meal, Ulgo lunged at the Ewok. Warok sidestepped the attack and inadvertently struck the Dulok with his glider, sending the king plummeting off a cliff into the canyon below. Initially, the Ewoks believed Ulgo would survive the fall by landing in deep water, but a strong gust of wind altered his trajectory, causing him to strike a large, flat rock, which resulted in his death. Chirpa then recited an oath for Ulgo, as was the Ewok custom for any forest creature that perished.
Despite his solitary existence in the Canyons of Mists, Ulgo maintained his claim to be the king of all Duloks. He regarded Vulgarr, another Dulok king, as foolish for trading a fine Ewok fur vest for a mere two lantern birds. When angered by the warriors of Bright Tree Village, the Dulok hissed and spat at them, threatening to repurpose their fur as foot wipes. Ulgo was an elderly, hunched, and wizened Dulok, characterized by his mangy fur and deep, growling voice.
Ulgo's character was conceived for the children's novel The Adventures of Teebo: A Tale of Magic and Suspense, authored by Joe Johnston and published in 1984.