Jay Garrick's trainee

An unidentified female individual on Earth-3 may have gotten her speed from a particle accelerator explosion on Earth-3, and Jay Garrick told Team Flash that he'd train her to take his place as the new speedster vigilante on his earth, while he himself would retire from being the Flash on Earth-3.

Powers

 * Speed Force connection/Meta-human physiology: This female speedster possesses a natural connection to the Speed Force, giving her the powers of incredible speed and superhuman reflexes.