When Luthor escapes from prison again, he reforms his criminal gang and arms them with a liquidified kryptonite substance as effective as natural kryptonite. Reminded of their earliest case together, Batman and Robin offer their assistance to Superman in the event that Luthor continues to use kryptonite against Superman.
When Batman and Robin summoned Superman to work out their collaborative attack to stop Luthor, they are surprised to see Superman arrive with Powerman. Superman unexpectedly claims that Powerman is his new partner and that Batman and Robin are no longer needed.
The surprise move does not deter Batman and Robin from continuing their investigation against Luthor, though not directly with Superman. Batman and Robin devise another effective defensive shielding against Luthor’s kryptonite ploy. With the threat of Luthor removed, Superman revealed to his friends that Powerman was a remote controlled robot he designed to safeguard them from harm.
While Superman continued to refine and use other robots, he retired the Powerman robot, accepting his steadfast friend’s loyalty to repeatedly risk their lives for him, despite any obvious dangers.
Another version of Powerman existed on earth 22. It is unknown if he survived the atomic bomb in Kansas.