Ezra Miller's Barry Allen/The Flash only made a brief cameo in Batman v Superman: Dawn of Justice, foiling a robbery at a convenient store and traveling back in time to warn Bruce Wayne (Ben Affleck), but based on reports from the Justice League set and from what we saw of him in the Comic Con trailer, it seems like Miller could be the lifeblood of the film, injecting some much needed fun into the DC Cinematic Universe.

We only got a taste of what The Flash-Batman relationship will be like in Justice League when we saw Barry's first encounter with Bruce, who broke into his apartment so that he could recruit the speedster. While promoting Fantastic Beasts and Where to Find Them, Miller provided more details on how the Scarlet Speedster gets along with The Dark Knight.

"I think it's the relationship between someone who is naive and excited and someone who is experienced and jaded," Miller told IGN. "And it's that seeing each other as reflections of one another and being amused and maybe sometimes annoyed by one another. I think Bruce and Barry get a kick out of each other because they're seeing sort of themselves but reflected in this very warped mirror. Bruce, the aged Batman, is everything that being a superhero means you could become, in terms of being pretty shut down and having seen all this horror. He's like a veteran of this struggle against evil. And Barry is just getting into it, and it seems exciting! And very fun! And so, I think they have a lot to learn from each other, like in any great friendship. I think it's a fascinating relationship."

Fueled by his restored faith in humanity and inspired by Superman’s selfless act, Bruce Wayne enlists the help of his newfound ally, Diana Prince, to face an even greater enemy. Together, Batman and Wonder Woman work quickly to find and recruit a team of metahumans to stand against this newly awakened threat. But despite the formation of this unprecedented league of heroes—Batman, Wonder Woman, Aquaman, Cyborg and The Flash—it may already be too late to save the planet from an assault of catastrophic proportions.