Injustice 3: 7 Story Directions Fans Would Love
5. Forever Evil
Forever Evil was a comic book event in 2013, similar to Marvel's Dark Reign era, however the story of Forever Evil follows an evil Justice League (the Crime Syndicate) coming to Earth from an alternate universe. This story probably wouldn't work in the Injustice universe though, as the whole 'evil heroes' thing has already been done.
While the original Forever Evil storyline may not be possible, framing the villains as the protagonists (in a Batman victory scenario) would certainly make for a fun ride. DC seems to leaning into their villainous side anyway, with the popularity surrounding Suicide Squad, the upcoming Joker movie and the Lego DC Super-Villains game.
This could take two routes, with the story either focusing on anti-heroes like Deathstroke and Deadshot, or actual villains such as Bane or Black Adam, who previously allied with Superman, especially as all of the aforementioned characters haven't really had much screen time of late.