Cyslin Myr, a Force-sensitive Mirialan female, was the Jedi Master who trained Padawan Mace Windu in the ways of the Force. At some point before the operation on Hissrich, Myr and her apprentice traveled to Mathas, a planet whose inhabitants were suffering from the Niffin plague. Together, they removed a man named Drooz, who was pretending to be a Jedi prophet and healer to trick the inhabitants into paying him for spiritual advice. They openly confronted Drooz and arrested him, after her Padawan, Mace Windu disarmed him and planned to kill him. She luckily talked Mace out of it, convincing him that is a matter to be taken up with the court of law.
Cyslin Myr’s first and only appearance in the Star Wars canon has been in a flashback sequence of the fourth issue of the 2017 Star Wars: Jedi of the Republic – Mace Windu comic book miniseries. In Star Wars Legends, Mace Windu’s Jedi Master was the NetiT’ra Saa.