12 Times DCEU Movies Completely Changed The Comics
8. The Kryptonian Growth Codex - Man Of Steel
Man of Steel introduced the concept of the Kryptonian Citizen Registry Codex (or simply the Codex) to the Superman mythos. The Codex is the skull of an ancient Kryptonian that contained the potential genetic information of the Kryptonian race (think of the skull as belonging to the genetic precursor to modern Kryptonians).
Kryptonians used this information to develop a system that saw the artificial creation of children that were then bred for specific tasks such as artists, warriors, and leaders. During the planet's final days, Jor-El bonded the Codex with his son Kal-El's genetic makeup with the intent of preserving the Kryptonian race after the planet's destruction.
The idea of the Codex and the artificial birth of Kryptonians is reminiscent of the bottled city of Kandor, a city captured by Superman villain Brainiac and the idea that Kryptonians experienced artificial births respectively. The bottled city of Kandor, in particular, is touted as a means for Krypton to be repopulated elsewhere in a manner similar to DCEU Jor-El's and Zod's plans to save their homeworld.