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For an overview of ZAX supercomputers, see ZAX.

Gametitle-VB.pngThe following is based on Van Buren and is not canon.
I had been built two years too late for the reason I had been created. And there was nothing I could do when the End came.— -ZAX

ZAX is the outdated supercomputer machine intelligence in charge of The Great Calculation, the Boulder Dome installation, and research of the New Plague in 2253.


Time kills machines as it kills humans, and I have felt the decay, the slow blindness, the inability to... remember— -ZAX.

This ZAX module was constructed somewhat erroneously two years before the discovery of the New Plague. Put simply, only two years after he was made, a better computer A.I. (ODYSSEUS) was created to outperform nearly all of the contemporary ZAXes.

As of 2253, the ZAX and ODYSSEUS had a competitive rivalry, where both were researching and making calculations about the New Plague. Of course, ZAX is way out of shape to even continue making the calculations he is, considering he doesn't remember why he even started them. ZAX even has had some of his security systems hacked by ODYSSEUS, and is fighting to protect himself from succumbing to memory cannibalization. Put simply, the player would learn that ZAX has spent so long in the effort of fighting off ODYSSEUS and studying the New Plague that he has used almost all of his memory banks and is beginning to overwrite his old memory banks as he continues to try and solve the calculation problem.

Interactions with the player character

Interactions overview

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This character starts quests.
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This character is involved in quests.


Other interactions

Being extremely important to the Dome's survival, ZAX is most likely to task the Prisoner with finding new memory storage units for it. Holodisks are one thing that the Dome scientists are willing to barter from you, but they are a weak, temporary fix, and not nearly enough for mass memory storage. When talked to, the ZAX can answer such questions as the origins of the plague, ULYSSES' purpose (also known as ODYSSEUS), and his calculation.


  • ZAX does not know that the New Plague and the Blue Flu are the same thing.
  • Even the scientists are oblivious as to what the calculation truly is.
  • ZAX is becoming somewhat of a schizophrenic because of the contradicting purposes Victor Presper "gave" him.


ZAX was going to appear in Van Buren, the canceled Fallout 3 project by Black Isle Studios.


Design Document
CharactersScientistsAgnes · Donald · Goddard · James · Nina · Paul · Think tank · Xian · ZAX
TruckersBillie · Eddie Galenski · Helen Wheels · Jack · Joshua · Ribera · Tanner · Tyler
JackalsBanshee · Crazy Bitch · Howler
LocationsBoulder Train Station · Jackal camp · Baggers camp · Dead ghoul graveyard · Boulder Dome level 1 · Boulder Dome level 2 · Boulder Dome level 3 · Dome tunnels · ZAX Mainframe
QuestsBoulder Scientists Research or Write · Code Yourself Smarter · Defeat the Baggers/Larsen's Team · Destroy the Jackals · Destroy the Truck · Dope RadAway for Larsen · Dump Allies In the Dome · Establish Radio Contact & Trade With Denver · Find out about Wagner · Find out what ZAX is calculating · Fix Things in the Dome · Get the Medical Implants · Give Slaves to Boulder to Make Robobrains · Heal Helen's Kids · Jimmy the Cannibal · Quarantine the Glow Bugs · Research Plague Data · Robobrain a CNPC · Sleep Through Presper's Holocaust · Stabilize the Reactor · Take Computer Classes · Tell the BOS about the Dome · Trade Holodisks to the Geeks · Use Think Tank for Data