Colli was a Tholothian male who resided on the river moon known as Al'doleem.
Colli's birth was to Jogg and Mareena, both Tholothians. In the year 19 BBY, he assisted his mother and father in managing their garage. When the Jedi Master, Kirak Infil'a, arrived, they welcomed him, and he shared the story of killing a Sith and his desire to eliminate the Galactic Emperor and bring back light to the galaxy. Colli was astonished, and Mareena stated their family never considered the Jedi traitors, after which they began repairs on Infil'a's ship.
Colli was surprised when Infil'a employed the Force, noting that even her father couldn't lift them without assistance. Infil'a responded that the Force lightened all things, outlining his intentions to reestablish the Jedi and later return to teach her the Force's secrets. Suddenly sensing Vader's approach, Infil'a dropped the materials, prompting Colli to shield himself and his sister. Colli entrusted the infant to her father, and upon their emergence, Vader challenged Infil'a to a lightsaber duel. Amidst the confusion, Colli questioned if Vader was the Sith, but Infil'a instructed everyone to return to the garage and repair the starship. Colli and his sister successfully escaped, although their parents perished when Vader submerged the city. Years later, he encountered Luke Skywalker, recognizing him as a Jedi. Colli recounted Infil'a's life-saving act and guided him to Mount Pasvaal.
Colli possessed brown eyes and a fair complexion. He donned a Tholoth headdress. Colli maintained that the Jedi were not traitors and had a positive relationship with Kirak Infil'a. He was impressed by Infil'a's use of the Force. It's plausible Colli was Force-sensitive, given Infil'a's offer to teach him the Force's mysteries and rebuild the order on Mount Pasvaal.
Colli's debut was in Darth Vader (2017) 4, a canon comic from 2017 penned by Charles Soule and illustrated by Giuseppe Camuncoli.