Protagonist

Character Role Analysis

Batman/Bruce Wayne

This isn't Batman vs. Superman, so of course Batman is the protagonist. You could also make a case for Vicki being a protagonist of sorts. We meet her before we meet Bruce Wayne, and as the audience, we most closely relate to her investigating the truth behind Batman's real identity.

But her name isn't on the poster. And it isn't called the Vicki Signal. So Batman's the protagonist.