Rosita has a PhD in Biochemistry and Engineering as well as an online certification in Astrology.
Rosita works as a bartender at Shorty's and collaborated with Doc Holliday and Jeremy Chetri to help create a serum for Xavier Dolls. At some point, Rosita and Doc develop a sexual relationship (first seen in Whiskey Lullaby) and continue the relationship even though Doc might have gotten Wynonna Earp pregnant. Doc encourages Rosita to bond with the Earp sisters, so she decides to throw a baby shower with Waverly Earp for Wynonna. In the episode Forever Mine Nevermind, Waverly learns that she's actually a revenant and helps keep Rosie's secret from Wynonna. Doc is in on her secret. However, in I See a Darkness, Waverly reveals to Wynonna that Rosita is a revenant, leading Wynonna to threaten Rosita with Peacemaker, telling her that if she tests a serum to cure Nicole, Wynonna will "shoot her last". She was planning to steal and sell Wynonna and Doc's baby for safe passage out of Purgatory, so it's safe to assume she is no longer in a relationship with him.
- Emily Andras has admitted, that she wrote the character of Rosita with Tamara Duarte in mind. Tamara herself, didn't know this until part way through filming.