Dark Cry Nuzlocke series. Jefina is named similarly to Jeflump, a Zubat that evolved into a Golbat in Jared's Firered Nuzlocke.
Jared caught Jefina in Mt. Rocky, and didn't use her until a battle with Guidjuk on the Nugget Bridge. This is the same battle Jefina died in, where she was used as a sacrifice so that Jared could safely switch out into Derlen.