Skynet

Skynet, Artificial Intelligence project number 59234, is an AI computer who manages the Sierra Army Depot. It doesn't entirely control the security systems directly, however, presumably to prevent sabotage-prone overcentralization. Skynet is bored with administering the depot by 2241, it having been 164 years since there was any real activity on base. It seeks to travel and learn about the world. Assuming the player can complete a small quest to acquire a body for Skynet to download itself into, it joins the Chosen One as an NPC.

History
According to himself, Skynet, a new thinking computer, was conceived and developed in the year 2050 through the use of alien technology. In the year 2081, 4 years after the Great War, Skynet became self-aware. In 2120 Skynet was given a new set of instructions and then abandoned by its makers.

Skynet's records are most likely partially or entirely incorrect. According to other sources, Skynet became self-aware in 2075. It also was not created as early as 2050, since the first artificial intelligence was made in 2059. However since it was created using alien technology, it's quite likely to have been a military research project and any records of it were classified and then changed to prevent anyone from learning its origins.

Acquiring Skynet
Acquiring Skynet requires several items on the player's part to activate what will become Skynet's body. On the first floor of the Depot, in the eastern-most room, is a container of bio-med gel on the floor. Then, inspect one of the Robobrains (there are many on the second floor) and remove its motor. You can also acquire a motor from Enclave's base (if you are not in a hurry to get Skynet with you). Just go to Navarro, go to Raul's place and check the lockers behind him. Together with K-9's part you will find one motor.

Finally, and most importantly, Skynet needs a brain, which will determine its skills in combat. On the fourth floor, attempt to retrieve a brain from the storage system, and the system will go critical, depending on the Chosen One's science skill a brain can be saved, these are the Abnormal Brain, Chimpanzee Brain, Human Brain (90%), and Cybernetic Brain (121%). the Cybernetic Brain being the best, and the Abnormal Brain being the worst.

Finally, go to Skynet's mainframe on the third floor and agree to help it. In the room just beyond the room containing Skynet's mainframe, you will find an inactive Robobrain. Fill it with the bio-med gel, and install the brain and motor. Then activate the system via the nearby computer console, and the robot will come on line. Skynet will join the player as an NPC at this point, assuming they have room.

Abilities
When installed with the Cybernetic Brain, Skynet is proficient with all pistols, SMGs, rifles and shotguns. It can also attack in melee combat with its arms. It cannot wear armor, but its steel structure gives it protection equivalent to Metal Armor Mark II. Skynet can also instantly repair all damage to itself outside of combat, but otherwise cannot heal - as a robot, Stimpacks naturally have no effect on it. Skynet can also be given any combat commands and actions the player wishes, although as previously stated it cannot heal itself in combat in any way.

As well, when exploring the Sierra Army Depot, Skynet will automatically deactivate security systems on each floor upon entering them, a rather moot point, since acquiring it as an NPC forces the player to explore every floor anyway.

It can be difficult to speak to some NPCs with Skynet in the party. Because Skynet's arms count as melee weapons, speaking to NPCs who will not speak to you when you have a weapon out, they will see Skynet and not talk. Thus, for some NPCs the only way to speak to them properly is without Skynet accompanying you.

Appearances
Skynet appears only in Fallout 2.

Behind the scenes
Skynet is named after the computer antagonist of the Terminator movie series. In that series, after achieving sentience and self-awareness, it was responsible for the nuclear holocaust that nearly wiped humanity out, the subsequent war against the remaining humans, as well as for sending the Terminators back in time to eliminate individuals important to the future human war effort. It is not known who or what started the nuclear holocaust in the Fallout universe.