WARNING: The following contains spoilers for Superman '78 #2, on sale now from DC Comics.
While Superman has one of the most robust, extensive rogues galleries in the DC Universe, the antagonist he keeps coming back to the most is Lex Luthor. This distinction is especially true for the Christopher Reeve incarnation of the superhero, with Gene Hackman's Luthor menacing the Man of Steel in some capacity in three out of Reeve's four films as the iconic character. While initially absent in the opening issue of the comic book continuation series Superman '78, Luthor resurfaces front and center in the sequel series' second issue in a surprising, new capacity as Superman decides to approach his old enemy with the shocking offer to work together against a common foe.
After a battle against the robotic, extraterrestrial enemy Brainiac, with the classic comic book villain finally making his debut in the world of Reeve's films, Superman is unsure of the origin of this enemy that caused so much devastation to Metropolis before being forcibly deactivated. With his own research methodologies in the Fortress of Solitude presumably exhausted without yielding any discernible results, Superman decides to turn to the self-proclaimed greatest criminal mind of all time with a shot of redemption and to learn about the origin of the robotic Brainiac drone. And in Superman '78 #2 (by Robert Venditti, Wilfredo Torres, Jordie Bellaire and A Larger World's Dave Lanphear), Luthor's life since the movies has been revealed.
Superman '78 is described as a continuation of the cinematic story since 1980's Superman II, eschewing the widely maligned sequels Superman III and Superman IV: The Quest for Peace. Superman II saw Luthor break out of prison and approach General Zod and his escaped convict associates to conspire in defeating Superman and conquer Earth in exchange for gaining control of Australia. Luthor appeared to work with Superman when the confrontation spread to the Fortress of Solitude but attempted to betray Superman to Zod. Anticipating this, Superman tricked both villains, defeating Zod and the villainous Kryptonians before turning over Luthor to the arctic patrol where he presumably was remanded back to prison to finish his sentence with some extra time on top for bad behavior.
Superman '78 reveals that Luthor has been released early on parole but his notorious criminal record makes him eligible for only menial work, with his trumped up genius intellect of little value to honest jobs. Increasingly frustrated and unable to catch a break, Luthor returns home to his apartment in Metropolis only to find Superman waiting for him with an offer to study the head of the Brainiac drone. After learning it was Superman who personally advocated for his early release, hoping the supervillain would find atonement, Luthor begins working on the Brainiac drone in his secret lab, only to accidentally activate it and broadcast a message to Brainiac himself, bringing the cosmic enemy straight to Metropolis.
Despite working with Superman, it's visibly clear that Luthor still deeply resents the Man of Tomorrow. Luthor is more amused than concerned when Brainiac broadcasts his ominous warning to the world, and speeds downtown to witness Superman being overwhelmed by Brainiac drones firsthand.
Superman is still optimistically willing to give his greatest enemy a chance at redemption but with Luthor's allegiances constantly shifting for his own benefit, he will likely turn on the Man of Steel again in order to inevitably save his own skin.