Masterbrain

Located in Vault-Tec Headquarters,  is a unique Robobrain that controls all the other security robots in that facility.

Interactions with the player character
The player can shut down Masterbrain using 3 terminals scattered throughout the building. It is also possible to disable it using the Robotics Expert perk, if you have a high enough sneak skill. Masterbrain will attack the player on sight.

Effects of player actions
If it is defeated, and you 'search' it, it will say: "You have accessed the Masterbrain's internal mechanism. If you destroy its uplink, it will cause all the automated security units in Vault-Tec to shut down." If you do so, this will disable all other robots in the Vault-Tec Headquarters building, but it will not disable the Automated Turrets.

Appearances
The Masterbrain only appears in Fallout 3.