In Injustice: Gods Among Us Superman kills Joker for murdering Lois and their unborn baby but he doesn’t stop there. He begins killing supervillains and superheroes alike in an effort to impose order. Batman resists but Superman finally puts an end to his interference in Injustice: Gods Among Us #35. Superman confronts his former friend and teammate in the Batcave.
“I took away all the madmen of Gotham,” he remarks. “But I left the original”
Batman stalls while the Batcomputer analyzes a pill designed to duplicate Superman’s powers but just before he can take it, Superman breaks Batman’s back over his knee! The scene is reminiscent of when Bane breaks Batman’s back in Batman #497. Although it’s unknown if that incident ever occurred on the parallel Earth on which Injustice takes place.