Superman controversially killed Zod in 2013's Man of Steel, but he had already ended the villain's life twice beforehand in the comic books.

Superman may be traditionally known as a big blue boy scout, but his relationship with the "no killing rule" has been contentious at times. The Man of Steel meted out violent retribution many times during the Golden Age of Comics, even though the Silver Age toned him down considerably. Nevertheless, he's explicitly killed a few of his enemies since then, with one fellow "Kryptonian" dying by Superman's hands on more than one occasion.

General Zod is usually portrayed as one of the few other survivors of Krypton's destruction, although his genocidal tendencies put him at odds with Superman more often than not. One controversial adaptation of the character was in Zack Snyder's Man of Steel, wherein Superman killed the villain to stop his rampage. This wasn't the first time that Superman did so, however, with the comics giving the villain far worse deaths.

Superman Literally Executed General Zod in the Comics

The first time that Superman put a permanent end to General Zod's villainy came at the end of John Byrne's post-Crisis on Infinite Earths tenure. This publication period for the hero was known for an editorial mandate that kept Superman as the sole survivor of Krypton. Thus, there were initially no Phantom Zone criminals, Supergirl or even Krypto the Superdog, making Kal-El the planet's "Last Son" in a way he hadn't been in decades. Nevertheless, some elements (including variants of the destroyed multiverse) would work their way into newer stories, leading to Superman ending up in a divergent "pocket universe." This Earth somewhat resembled the pre-Crisis Earth of the Silver Age, but its Superman (actually called Superboy) was nowhere to be found and a heroic Lex Luthor was humanity's last hope against three Kryptonian criminals who had escaped from the Phantom Zone under the leadership of General Zod.

Due to these pre-Crisis Kryptonians being at a far greater power level than the main continuity Superman, they ravaged everything in sight even after he entered the fray. His only hope was gold Kryptonite, which he used to depower his three foes, who vowed vengeance against him. Ensuring that they would never live to regain their powers and threaten another world, Superman also employed green Kryptonite, which poisoned and killed the fiends. This wasn't what officially killed Zod, however, as his associate Quex-Ul blamed him for their defeat and strangled him to death as the two succumbed to the radioactive element.

Zod's Second Death in the Comics Was Even More Brutal

Before finally bringing in a version of Zod based on Terrence Stamp's portrayal of the villain in the Richard Donner Superman movies, DC introduced other divergent takes that still flirted with the "no other Kryptonians" rule. One of the last examples of this was Avruiskin, also known as the "Russian Zod." His parents were cosmonauts who seemingly suffered from radiation poisoning following a meteor shower that also brought Kal-El's ship to Earth as a baby. This corrupted Aruvskin's genetics to where he was excruciatingly weak under a yellow sun, but had powers equal to Superman's under red sunlight. One day, he was contacted by the spirit of the pocket universe Zod, and he took his name in honor.

This Zod's ultimate plan was to turn Earth's sun red, empowering himself while weakening and depowering Superman. Lex Luthor was able to reverse the process, and this led to the second Zod's final defeat. Previously, Superman had the opportunity to snap the villain's neck (an act which he would do in the aforementioned Man of Steel), but refused to do so. Zod likewise refused to yield, flying into Superman's back at superspeed just as the sun was turning yellow again. The impact of the now mortal Zod slamming into Superman killed the villain, with his bones and body instantly broken. This was one of Zod's most brutal endings in the comic books, and it's arguably far worse than what occured in Zack Snyder's film. From these stories, it's clear that even Superman has days in which his enemies meet their final fate, with General Zod being the usual "victim." The death of Zod might have been handled differently in the DC Extended Universe, but it still has its roots in the comics.