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Fallout Wiki

XPN-20A is a synth within the Institute in 2287.


XPN-20A is a hostile synth encountered in the Institute's reactor room during the quest The Nuclear Option with any faction. XPN-20A, along with A-2018 and Z4K-97B, will serve as the game's final boss during all endings other than the Institute ending.

Interactions with the player character[]

Interactions overview[]

FO76 ui icon quest
This character is involved in quests.


Apparel Weapon Other items On death
Synth uniform


XPN-20A seems to posses unique carbon fiber variants of standard synth armor. These are unobtainable, given that the unique armor is actually part of its model. One can pacify XPN-20A with the Wasteland Whisperer perk, but equipping new armor to the player character will just layer it over the unique armor. The unique black armor will not appear in the player character's inventory, regardless of acquisition techniques.


XPN-20A appears in Fallout 4 and Fallout Shelter Online.


PCPC Playstation 4Playstation 4 Xbox OneXbox One Unlike Z4K-97B and A-2018, XPN-20A does not spawn in the reactor room, but next to the elevator at the center of the main floor, before going into the Advanced Systems wing.[verified]


Institute flag
Fo4 Institute Seal