Gotham Season 5 will apparently draw its inspiration from Batman: Zero Year.
The series’ fourth season borrowed elements from Batman comic books The Killing Joke and No Man's Land. While the No Man's Land arc will continue to exert an influence on the upcoming season, the show will incorporate an additional popular comic book storyline.
Asked during a recent conversation with ComicBook whether there were fresh sources of inspiration for Season 5, executive producer John Stephens revealed that it will borrow from Scott Snyder and Greg Capullo's Zero Year:
You mean besides No Man’s Land? There are, and I’m trying to remember which [stories] they actually are. There’s gonna be a little bit of Zero Year in there…as well. [You know] some of that stuff, especially with Nygma. And there’s another one, but if I tell you what it is, it really does spoil the story.
We’ve already had confirmation that the coming season will be Gotham’s last, and the show will focus on how Bruce Wayne (David Mazouz) becomes Batman. Zero Year’s second arc, Dark City, is about Bruce's beginnings as the Caped Crusader, so it makes sense that the New 52 storyline will come into play during the show’s final season.
Edward Nygma, aka The Riddler (Cory Michael Smith), also had a prominent role in the previous season’s plot, and based on the EP’s comments, it appears that the character might be the next season's big baddie.
During the recently aired Gotham Season 4 finale, The Riddler and Lee Thompkins had a violent knife fight, and Hugo Strange wound up taking possession of what was left of them. Everyone knows that Strange is literally a monster maker, so it would be no surprise if a more powerful and wicked Nygma turned up in the streets of Gotham City. The villain’s return would certainly act as a catalyst for Bruce’s inevitable transformation into Batman.