Mostima, a Jedi Master of the High Republic Era, was a female human. She began training Sean as her Padawan in 203 BBY. Later, in 200 BBY, Mostima and Sean were dispatched to address the issues with Jamie Brasson, the dishonest president of Begamor, and subsequently, they were assigned to probe a homicide within the Aakaash system.
The initial appearance of Mostima was in The Vow of Silver Dawn, a Chinese web-novel penned by "His Majesty the King" and released on December 22, 2020.