|Appeared in||Man of Steel|
The Growth Codex or Registry of Citizens Codex is an ancient Kryptonian artifact that decodes the genetic makeup of the artificially incubated babies on the planet. It translates a child's genetic attributes before his or her birth. Zod was born to be a soldier, as dictated by the Codex. Zod needs the Codex in order to shape the genetic future of a reborn Krypton population.
When Kryptonians created the technology to create new life forms from a genetic matter, the planet stopped producing offspring naturally.
When a massive terraforming project was activated to spread Kryptonians throughout the galaxy, a Growth Codex was installed into every scout ship along with the genetic matter to create a new Kryptonian civilization on a chosen planet.
Just before Krypton's destruction when General Zod, military leader of the planet decided to overthrow the Kryptonian Law Council. The scientist Jor-El opposed Zod's plans and stole the main Codex and placed it in a ship along with his newborn son Kal-El and sent it to Earth out of Zod's reach, who was shortly sentenced to 300 years imprisonment in the Phantom Zone for murder of Jor-El and others.
Zod and his forces escape from the Zone and tracked Kal-El to Earth and searching his ship, could not trace the Codex which had in fact been placed in Kal-El as a baby meaning he carries the sole hope for Krypton's future.