Remember, it can be triggered with or without using a weapon. Discovering Black Flash will render it accessible. You'll know it's been unlocked when a cutscene appears while you're using the M1 move.

Wally West beat the Black Flash by racing him to the end of time, essentially rendering death useless. Barry Allen, on the other hand, became the Black Flash at one point. I don't see that ...

Barry Allen’s got yet another speedster problem: The Flash executive producer Andrew Kreisberg reveals that Season 2 villain Zoom will resurface as the Black Flash — and in a big way ...