7. John Jones/ Martian Mahunter
You may know him as Martian Manhunter, or even as Jonn Jonzz, the last of an extinct race of Martians. His core role in the Justice League is to gather intel, direct the team where theyre needed and of course to get involved in the battles when hes needed; with psychic powers, super-strength, the ability to phase through solid matter and to shape-shift (amongst other things), as a combatant Jonzz is probably about as tough as Superman himself. But, for years before the JLA formed, Jonn Jonzz appeared among us in human form as John Jones, a hard-boiled detective, in attempt to fit in on our planet. Itd be easy to fit this in to the Man of Steel with just a few quick lines of dialogue. Maybe John Jones could question Clark Kent about something trivial to the Man of Steel plot, maybe hed need rescuing at some point (hed be forced to hide his true power to protect his identity), or maybe Superman is approached by Jones, who has telepathically discovered his power, and reveals himself to be an alien too. It could be a quick little moment, but without the Manhunter, theres no Justice League, so you could say itd be apt.