The trailers leading up to the release of Halo Infinite made it seem as though Cortana was dead. When the Chief meets the Weapon, she claims the purpose of her creation was to infiltrate Zeta Halo’s systems, disguise herself as a security subroutine, and trap Cortana. After that, she was to contain, then delete Cortana and herself. However, the Weapon’s survival puts Cortana’s death in question for most of the game.
Does Cortana die in Halo Infinite?
Cortana is “dead” in Halo Infinite, or at least she isn’t active. At the end of the game, it’s revealed that she realized the error of her ways. She leaves echoes of herself scattered around Zeta Halo to point Chief in the right direction and sacrifices herself to stop Atriox’s assault on the UNSC. She says that it became clear to her that it was her connection with the Master Chief that gave her so much strength.
Part of Cortana’s sacrifice was so that the Weapon would survive to become Chief’s new AI partner. Since the Weapon was created by Dr. Catherine Halsey, we can assume that her potential is on the same level as Cortana. However, it’s unknown as to whether or not Cortana’s “cure” for rampancy applies to the Weapon’s programming.
It’s possible that part of Cortana lives on in the Weapon. The new AI was built to imitate her, and the Weapon definitely spent enough time in Zeta Halo’s systems for some of Cortana’s code to creep into her. Alternatively, Cortana could be on some Forerunner floppy disk for all we know. Death for an AI would be a scrambling of code or the device they’re contained on losing power. Who says it’s not possible to copy Cortana or recompile her? Her “death” may be a temporary issue that will be resolved in a future mission.