The Brotherhood of Steel is not a single entity on Prime Video’s Fallout. The order consists of different chapters, each with its own leaders. But the paramilitary organization is now ready to unite under one powerful banner. Mostly. In Fallout season two, episode two, Quintus convinced the other factions to unite against a common enemy, the most powerful Brotherhood chapter, The Commonwealth. In the world of the games, The Commonwealth refers to a Fallout location. But in the series, the phrase ‘The Commonwealth’ becomes something more to the Brotherhood of Steel. But what is The Commonwealth in Fallout season two’s world, and why were the Brotherhood’s leaders initially so afraid to cross it? And what did the arrival of The Commonwealth’s liaison, played by Kumail Nanjiani, mean for a possible civil war in the Brotherhood? Death, one way or another.
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Fallout Season 2 Introduces Us to ‘The Commonwealth,’ A Chapter of the Brotherhood of Steel
Maximus gave his Chapter of the Brotherhood, the Knights of San Fernando, cold fusion technology in Fallout‘s season one finale. Elder Cleric Quintus is already taking advantage of having unlimited power. With the piece of technology Maximus found in season two’s second episode, the Brotherhood chapter can now control the strongest armada in the world. But Quintus has even bigger plans. He wants to bring all the other Brotherhood chapters together to work alongside them so they can control the Wasteland.
The leaders of those other factions were not eager to join with Quintus, especially not when they fear the group’s strongest chapter. The other Elder Clerics believed they had no shot, even fighting together, against The Commonwealth chapter of the Brotherhood of Steel—what they refer to simply as “The Commonwealth.”
What Is The Commonwealth in the Fallout Games?
The Commonwealth Is Actually a Location in the Fallout Games
The Commonwealth is actually the primary location of Fallout 4 in the world of the games. It’s the territory located in the former state of Massachusetts. The region and its capital city of Boston were major players in American politics even before the Great War. It remained so after the bombs dropped. Over the last two centuries, different factions and communities—some extremely dangerous and powerful—have gained and lost influence over the region.
The Brotherhood Takes Control of The Commonwealth in Some Fallout 4 Endings
After decades of conflict, the war for The Commonwealth reached a tipping point in 2287 (when Fallout 4 takes place). That’s when three factions fought for control. One of the main reasons for the war’s escalation was the actions of a Brotherhood chapter from the former Washington DC. In Fallout‘s world, The Brotherhood had already established itself in The Commonwealth area by 2280, so the order was not unknown to the region. But over the next seven years, various recon missions that ended in death and missing Brotherhood members led the group to establish an outpost inside the Commonwealth.
Like with Fallout: New Vegas, there are multiple possible endings (each with their own variations) that a player can unlock in Fallout 4. In some Fallout 4 endings, the Brotherhood takes control over the Commonwealth. We don’t know if Prime Video’s Fallout will treat one of those endings as canon, but it’s not doing that with Fallout: New Vegas. The show is using a “fog of war” approach to make it so no video game ending is definitive. It could very well do the same with Fallout 4. In total, nine years have passed between the end Fallout 4 and the present timeline of the Fallout TV series. A decade is a lot of time.
What Do We Learn About The Commonwealth in Fallout Season 2?
What happened nine years ago is less important than what we’ve learned about the Commonwealth Brotherhood at the time of Fallout season two. The Commonwealth chapter of the Brotherhood told (and essentially ordered) Quintus’ chapter to go find Siggi Wilzig in Fallout season one after the Enclave scientist escaped with the cold fusion tech. But now we know that The Commonwealth chapter of the Brotherhood is not just more powerful than Quintus’ group in the Fallout TV series. We learn in Fallout season two that The Commonwealth is more powerful than all the other Brotherhood factions combined. Powerful enough that in the Fallout series, the phrase “The Commonwealth” stops referring to just a location, and starts referring to the chapter of the Brotherhood located there.
The Commonwealth Is a Chapter of the Brotherhood in the Fallout Series, and It’s Large and In Charge
The other leaders laughed at Quintus’ proposal to unite against “the Commonwealth,” a telling phrase. As mentioned, by simply calling that faction “the Commonwealth” in Fallout season two, it seems as though the Brotherhood is now synonymous with the Commonwealth itself. It’s the ruling power of the important region. (Possibly thanks to some very sought-after tech.) The other leaders didn’t want to have a civil war with the Commonwealth anyway, because even as one united force, it would easily lose to their Boston-based brethren.
That was until Maximus gave his chapter of the Brotherhood cold fusion in Fallout season one. Now Quintus can make more fusion cores than they could ever need. That means more power suits, more ships, more weapons, and more firepower, which could allow them to usurp the Commonwealth as the dominant Brotherhood force in Fallout season two. The other chapters liked the sound of that and finally agreed to Quintus plan for civil war. Even though The Brotherhood’s codex forbids any chapter from fighting another… When you have unlimited power, the codex is open to interpretation.
Kumail Nanjiani Plays a Liaison of the Commonwealth on Fallout Season 2
The united Brotherhood army couldn’t catch its common enemy by surprise, though. The Commonwealth somehow knew about the meeting it wasn’t invited to on Fallout season two. Did it intercept messages? Have spies in the other chapters? We don’t know yet. Kumail Nanjiani’s Xander Harkness, a liaison from the Commonwealth, showed up unexpectedly at the end of Fallout season two, episode two, ready to discuss the possibility of Brotherhood civil war.
But who exactly does Kumail Nanjiani play on Fallout season two? The Brotherhood’s Xander Harkness, of course, hails from the Commonwealth chapter. We don’t get to know him very well during his time on Fallout season two, but he paints a picture of the Commonwealth that is not flattering. Basically, through Xander, we learn that the Commonwealth’s chapter of the Brotherhood is EVEN MORE focused on brute strength and being meatheads than Maximus’ group. He explains to Maximus that in the Commonwealth, it’s “guys like them,” the ones out there doing the punching and fighting, that really count and get to be in charge. Xander makes it clear that, at least from his POV, the Brotherhood is allowed to follow their whims to destroy anything they want, as long as it tickles their fancy.
Xander Reveals That the Commonwealth Chapter of the Brotherhood Is Also Struggling in the World of Fallout Season 2
Xander does reveal one interesting thing about the Commonwealth chapter of the Brotherhood, though. He tells Maximus, “We are really up against it back home. Without the relic you found, we risk losing the Commonwealth… And if the Commonwealth falls, civilization won’t last much longer.” Well, we don’t know about that last part. But it’s fascinating to hear that even though the Commonwealth appears to be the strongest chapter of the Brotherhood, it’s ultimately not that strong at all. Like every other faction and chapter out there, the Commonwealth’s Brotherhood is struggling.
Is Civil War on the Way for the Brotherhood on Fallout Season 2?
The Commonwealth may be weaker than we first thought. But we might be about to find out firsthand what their strength looks like exactly. Maximus and Xander find themselves in Thaddeus’ soda cap factory, and Xander wants to blow up all of the “abominations” or Ghouls, even though they are mostly children. Maximus, whose moral code is stronger than that, intervenes and ends up killing Xander. Oops. Elder Cleric Quintus had basically said that killing the Commonwealth’s liaison would mean Brotherhood Civil War in Fallout season two. We don’t yet know what will happen next, but it doesn’t look good.
Whatever the Commonwealth decides to do on Fallout season two, and no matter the fate of any of its factions, the Brotherhood’s quest to save the world from itself seems certain to result in a lot more people dying.
New episodes of Fallout season two drop Wednesdays on Prime Video.
Mikey Walsh is a staff writer at Nerdist. He would like to at least try the Brotherhood suit of armor once. Maybe twice. You can follow him on Bluesky at @burgermike. And also anywhere someone is ranking the Targaryen kings.
Originally published December 25, 2025.