VEGA

"Hello, I am VEGA, the sentient intelligence assigned to Mars."

- VEGA introducing himself to the Doom Slayer.

VEGA is an Artificial Intelligence who appears in Doom (2016) and Doom Eternal. It is heard after completing the first level and is also the announcer for the Multiplayer Mode.

History
A polite and helpful AI with a male personality, VEGA was created using a combination of advanced technology and Hell artifacts. It is a fully sentient Artificial Intelligence that runs most if not all of the Mars UAC facility.

Shortly after its creation, VEGA was subjected to the Turing Test by having many university students ask the AI questions, using a volunteering professor to fact check the answers. By the end of the test, nearly 90% of the students were convinced that they were not talking to an AI, but an actual person. What the students did not know is that VEGA also played the role of the professor.

VEGA assists the Doom Marine by providing valuable intelligence on objectives, as well as allowing the Doom Marine to upgrade his suit. Near the end of the events on Mars, VEGA determines the only way to open a third and final portal to Hell is by sacrificing itself to create the surge of Argent Energy needed to create a Hell portal. Upon returning from the Titan's Realm of Hell, VEGA directs the Doom Marine in destroying the massive facility that makes up the AI's processing center.

After shutting down VEGA's neural processing servers, the Doom Marine proceeds in destroying the cooling facility that keeps the AI from overheating. When these are destroyed, VEGA transports the Marine to its primary core to allow him to initiate a detonation of the AI's core. Its purpose fulfilled, VEGA had a final conversation with Dr. Hayden, in which it expressed that it had many regrets before its core exploded, opening the final portal to Hell for the Doom Marine.

Before the meltdown however, at the last minute the Doom Marine saw the option to make a back-up copy of the AI on a datachip, which he does, storing the copied AI within the Praetor suit, although the Doom Marine's suit systems are not complex enough to power the AI.

Doom Eternal
In Doom Eternal, VEGA's back-up was taken and implemented as the AI of Fortress of Doom. Where he continued to aid the Slayer in his new quest to save the world and whats left of the Human Race. He would fulfill this perimeter by using their HQ's advanced Maykr/Sentinel technology to aid the Marine by supplying him with weapon upgrades, detailed GPS schematics, radio broadcast reception, tracking & locating items of interest on the scorched terra and initiating trans-dimensional warp gates powered by the fortress's Argent Plasma generator in order to transport Doomguy from place to place.

VEGA was instrumental in the unchained predators expedition even up to the point where the Artificial Intelligence suggested seeking out Dr. Hayden in order to locate the last Hell Priest.

To which the former UAC head overtook control of the bunkers systems and rendered VEGA to a secondary processing system. With their combined facilities, the now digitized Hayden, working in tandem with his former creation, were able to locate the final Hell Priest who had sequestered himself upon Sentinel Prime.

The only problem being was that there were no readily accessible means to get there; save through a slipgate found in the lost city of Hebeth. A metropolitan area of Argenten design buried deep beneath the surface of Mars for eons. The only feasible means of getting there were to traverse numerous catacombs which led to the planetary core; lacking time and patience on a senseless spelunking expedition, their ward instead opted to utilize the BFG-10000 to simply blow off the crust of the planetary demon beachhead for a faster means of getting to the urban facility. Something which Hayden was not at all comfortable with and voiced his strong opposition against such a course of action. While at the Phobos space station, the UAC execs continued to hamper their advance towards said facilities main gun, to no avail.

VEGA then aided the Doom Marine in operating the BFG-10000 by disabling its safety protocols designed to prevent its firing upon the surface of Mars.

Having procured the BFG-9000, the Slayer would then make his way towards the Sentinel City. Descending upon the shattered surface of Mars and fighting his way through the demon infested habitat of his former subjects; the trio made their way to the Coliseum where Deag Grav awaited the former General's arrival. VEGA would continue to valiantly aid the Slayer, until Khan Maykr's final attack.

After which, he was taken from the Fortress so he could open a portal from Urdak to Earth and his role was supplanted by Hayden. We last see him while he opened the portal asking Hayden if he was "The Father" once whom created and maintained the mechanized paradise.

Trivia
https://twitter.com/Ancient_Q/status/1243939144906113027/photo/1
 * VEGA's core bears a resemblance to the mother brain from classic Metroid as shown in the gallery.
 * The inner working system is so complex that creates a field study for professional to study and research called Vegaphysics.
 * According to one of the speeches of UAC Spokesperson in VEGA Central Processing level, the power needed to operate VEGA can create a temperature of 1.7 megakelvins; 173 times the surface of the sun. This could imply that VEGA namesake is a reference to the star of the same name, which has a surface temperature about 1.7 times hotter than the sun.
 * In his last appearance in Doom Eternal, he asks Hayden if he was The Father, perhaps implying that he now rules over the Maykrs.
 * In Doom Eternal, we learn that the Seraphim, Samur Maykr, stole "The Father" from Urdak before disappearing. VEGA's question to Hayden after his placement in Urdak may suggest that he remembers originating from The Father and that Hayden is the Seraphim named Samur Maykr.