Scientist Jor-El discovered that, after years of mishandling natural resources, the planet's core had become unstable and was on the verge of collapsing. Jor-El confided in Dru-Zod, a childhood friend and leading military figure who also dreamed of saving the planet.
Whereas Jor-El put his faith in science, however, Zod believed that force was the only way to ensure the survival of his people. Losing faith in the Law Council, Zod established the Sword of Rao and planned to initiate a coup that would depose the council.
Zod and his followers invaded Kandor and stormed the Legislation Chamber, interrupting Jor-El's plea for control of the Codex. Killing High Eminence Ro-Zar, Zod announced that the Council had been disbanded before inviting Jor-El to join their cause.
When the latter refused, Zod ordered his men to take him away while his second-in-command, Faora, took the surviving council members into custody.
Outside, resistance from the Warrior Guild caused a fierce battle to break out on the ground and in the air above Kandor. As Kryptonian Hammerheads respectively operated by the loyalists and the military engaged in combat, Jor-El escaped on his pet H'Raka and stole the Codex from the Genesis Chamber before retreating to the House of El Citadel.
Leading a squadron to the citadel, Zod arrived to see Jor-El preparing a spacecraft for launch. Jor-El revealed that he and his wife Lara had conceived a natural born child with the purpose of sending it and the Codex to another planet.
Zod ordered his men to destroy the craft only to watch as Jor-El gunned them down. The two engaged in a duel that ended with Jor-El holding Zod at gunpoint. Despite Zod's protests, Lara finished preparing the spacecraft and activated the engines.
Enraged, Zod fatally stabbed Jor-El in the stomach and emerged from the citadel, intent on destroying the craft. Before he could do so, however, the Warrior Guild placed him and his forces under arrest.
The surviving members of the Law Council were released, Lor-Em replacing the late Ro-Zar as High Eminence. Both Zod and his surviving followers were sentenced to 300 cycles of "somatic reconditioning" for the crimes of murder and high treason. Before being loaded aboard the Black Zero, Zod expressed his disgust towards the Council and vowed that he would find Kal-El.
It was shortly afterward that Krypton's core imploded and the planet was destroyed, indirectly freeing Zod and his surviving followers from the Phantom Zone.