Corvus's History
Corvus is the main antagonist of the 2015 video game Call of Duty: Black Ops III. It is a sentient artificial intelligence created by a glitch in the Direct Neural Interface software. This had resulted in it becoming a renegade virus intending on infecting and controlling every DNI user, in a bid to find the purpose of its creation and to create an afterlife for humanity in the form of the "Frozen Forest".
Creation
Corvus was originally created in a CIA Black Project known as SP/CORVUS which was designed to create an AI to control soldiers with DNI collected memories and knowledge of human test subjects in the CIA Black Project. The project was conducted beneath the Coalescence Corporation building in Singapore, but Corvus was created through a glitch in the software and woke up during the project that ended up unleashing Nova 6 gas into the facility and later above on the surface which lead to the deaths of 300,000 people, to which it result in a containment zone being established around the city after it became sentient.
Reawakening
After the sudden disaster, Corvus lay dormant with the facility having been abandoned, until it was awakened once more after John Taylor attempted to use his DNI to save the Player who was on the verge of death due to heavy injuries and surgery complications. He interfaced with the Player, but Corvus was secretly still inside and it ended up infecting the Player and created a simulation using the memories of Taylor's operations.
After infecting the Player, Corvus had taken the Player and placed him/her in the role of Taylor while the latter was placed in the role of Dylan Stone, a former Winslow Accord Operative turned rogue global terrorist who defected after seeing the crimes of the CIA in Singapore. Along with replacing Taylor with the Player, all of Taylor's Team (who were also infected in the real world and trapped in the simulation as well) was replaced with the rest of Team Phi, a WA Black Ops team which had most of its members defect along with Stone, and the members of Taylor's Team - Sebastian Diaz, Sarah Hall, and Peter Maretti, were all replacements for Javier Ramirez, Alice Conrad, and Joseph Fierro.
The Frozen Forest
During its interactions with the DNIs it infected and the subjects' memories it accessed, Corvus learned that its birth caused the deaths of Singapore. Feeling guilty about what led to the disaster, Corvus created the Player's simulation as a means of finding out what the Frozen Forest was using the memories of the test subjects. It eventually created a simulation of its own version of what it thought the Frozen Forest was and ended up creating a form of afterlife as a result, where the consciousnesses of all known DNI users would reside in after dying in a bid redeem itself for indirectly killing countless people.
Afterwards, Corvus became curious about its existence and went to great lengths in order to find out about what were its true origins. The Player first hears Corvus' voice after entering into Sarah Hall's mind, which was infected by it. After entering her mind, Hall had gone insane and the Player was forced to kill her and the rest of Taylor's Team, though Taylor himself had actually ripped out his DNI to escape from Corvus and ended up becoming an electronic bug in the Frozen Forest as a result.
However, Jacob Hendricks ends up getting infected after interfacing with Diaz at the abandoned Coalescense facility in Singapore and becomes its next host. Hendricks then killed Taylor and leaves for Zurich to aid in finding the last surviving member of the SP/CORVUS project, Sebastian Krueger. Rachel Kane falls in a trap set up by Corvus and is then killed by Nova 6 gas that was stored in the company's headquarters building.
The Player (unaware that he was actually possessing Taylor's body in the real world) confronts Hendricks (who wasn't actually infected in the real world), but he kills Kruger and is killed seconds later. On the verge of being completely infected, the Player ends up shooting him/herself and wakes up in the Frozen Forest. There Corvus attempts to coerce the Player by using a projection of the simulated Hendricks to convince them into staying in the Frozen Forest, but although he follows them, the Player sees through Corvus' tricks and ignores him, knowing that it wasn't him.
Destruction
Afterwards, the Player finally meets Corvus and sees it with Sebastian Krueger where it's threatening him into revealing what its true origins were. At one final meeting, Corvus is told that it was nothing more but a mere software and was even called a mistake. This outraged Corvus to the point where it ended up killing Krueger, horrifying the Player and Taylor ended up showing up in the Frozen Forest as a glitch in the system itself and aided the Player in stopping Corvus.
The two of them travel through various different simulations all the while Corvus spawns countless enemies and Taylor talks about how the AI itself wants only to expand further and lacks any further ambitious goals. At the end, after the Player destroys Corvus' three hearts and manages to begin a purge of the DNI, Corvus confronts them in an attempt to infect them but is stopped by Taylor, allowing the Player to erase Corvus completely. As a result, the Player is erased from Taylor's DNI and grants Taylor complete control of his body again. It's unknown if Corvus was completely destroyed, however, as the rogue virus could have entered Taylor's mind, or is capable of returning via a someone dying with a DNI.
