Fastän Superman är en fristående film som kommer att fokusera på just honom så är filmen proppad med flera andra hjältar. Hawkman, Supergirl, Mister Terrific och Guy Gardners Green Lantern är ett par exempel på DC-hjältar som kommer vara med i filmen. Nathan Fillion kommer spela den kaxiga och dryga Guy Gardner och i en intervju med TV Line berättade han mer om karaktären.
"He's a jerk! What's important to know is, you don't have to be good to be a Green Lantern; you just have to be fearless. So Guy Gardner is fearless, and he is not very good. He's not nice, which is very freeing as an actor because you just think to yourself, what is the most selfish, self-serving thing I can do in this moment? And that's the answer. That's what you do in that moment. I think if he has a superpower, it might be his overconfidence, in that he thinks he could take on Superman. He can't!"