A Force-sensitive Weequay, Yollo was trained in the ways of the Force by the Jedi Order, eventually attaining the rank of Jedi Master sometime before 3643 BBY. During the later stages of the Cold War between the Galactic Republic and the Sith Empire, Yollo resided on the Jedi homeworld of Tython. Selecting the young Spanios as his Padawan, Master Yollo and fellow Master Silvarte became suspicious of their students, believing that both Padawans Spanios and Moracen had begun a romantic relationship. To get an idea of the situation's severity, Master Silvarte sent another Padawan to discover whether the two apprentices were indeed romantically involved.
- Star Wars: The Old Republic (First appearance)