The sibling, a Tholothian baby, of Colli resided on the river moon known as Al'doleem.
Prior to the dawn of the Imperial Era, this baby was born to Jogg and Mareena. In 19 BBY, while her father was watching the baby, he heard sounds and emerged holding the infant. To his surprise, Jedi Master Kirak Infil'a had returned to repair his ship; it had been years since their last encounter, and most of the Jedi had been killed during Order 66. As they worked on the starship, the baby was fascinated as Infil'a used the Force to levitate objects. Sensing the arrival of Darth Vader, Infil'a immediately dropped everything he was lifting. Colli, protecting the baby, fled to prevent harm to either of them. Witnessing Vader challenging Infil'a, they all retreated into the garage to finish repairing Infil'a's ship. The infant and her brother managed to get away, but her parents perished when Vader destroyed a dam, flooding the city.
The first appearance of Colli's sibling was in Darth Vader (2017) 4, a canon comic from 2017 authored by Charles Soule and illustrated by Giuseppe Camuncoli.