Factions are a pretty common element in a lot of post-apocalyptic stories, especially ones that follow the zombie apocalypse narrative. Humans naturally gravitate towards community, and when the world is overrun by infected, there's certainly strength in numbers. Factions make sense in a story like The Last of Us 2, and they play a huge part.
When factions are involved, there is always an "us" and a "them." As a result, a lot of factions present in The Last of Us 2 have a military focus. When infected could ambush at any time, it's incredibly important to be armed and have a secure space to call home and prevent intruders from coming in. Resources are limited in this world, and humans have learned to never underestimate what others might do to survive. Ultimately, that's the reason all of these factions came into existence and have lasted far beyond the initial outbreak of the cordyceps brain infection.
The Washington Liberation Front (WLF)
The Washington Liberation Front, abbreviated as WLF or "Wolves," is the primary antagonistic faction in The Last of Us 2. Abby and her friends are introduced at the beginning of the game, and the first half is spent viewing the faction from Ellie's point of view. It's when players switch to Abby the WLF really begins to take shape, though.
Essentially, the WLF runs Seattle. The group is lead by Isaac, a briefly introduced character who is said to enjoy torture and initiates the attack on Haven, the Seraphite island. The Wolves place a huge emphasis on military practices and training.
Similar to the Fireflies, the Wolves came to power when Isaac, along with Emma and James Patterson, began to revolt against the way the Federal Disaster Response Agency (FEDRA) was operating Quarantine Zones. They rebelled and began spreading Anti-FEDRA propaganda around Seattle. After a long and violent revolution against FEDRA, the WLF gained control of the city. In the Last of Us Part 2, everyone in Seattle who isn't a Seraphite is a member of the WLF.
The WLF is headquartered in SoundView Stadium. It's powered by sustainable energy, has a food court, and an outdoor kennel for all of their dogs. The WLF is highly organized, heavily armed, and very dangerous when provoked. The faction has various other stations scattered throughout the city, so staying in Seattle for any amount of time is likely to warrant an encounter.
The Seraphites
The Seraphites are less of a faction and more of a cult, but their presence is more than significant. The Seraphites, referred to as "Scars" by WLF members, are a religious group that lives on an island called Haven, just off the coast of Seattle. The cult began shortly after the outbreak reached Seattle when an unnamed "prophetess" began preaching that the cordyceps infection was brought on by mankind's sinful living and dependence on technology.
As one might expect, the Seraphites value living apart from technology and modern civilization. They live in primitive structures and primarily fight with axes and bows and arrows. Men are required to shave their heads, and every Seraphite has a scar on both of their cheeks, which explains the WLF nickname.
The group follows the teachings of the now deceased prophetess and frequently says things like, "May she guide us" or "May she protect us." While the original Seraphite members joined of their own free will, a new generation is being brought up in the culture's ways and must follow the orders from the elders. This ends up being a huge problem for Lev, a transgender character commanded to become a wife to one of the elders.
Seraphites also whistle to each other in Last of Us 2 combat encounters to inform their allies of where they are and what their status is (an alert whistle sounds very different than a general headcount). Overall, the Seraphites are an unsettling group with a rich history and culture unlike anything else seen in The Last of Us 2.
The Rattlers
The Rattlers are a particularly disturbing faction players encounter towards the end of The Last of Us 2 in Santa Barbara. They aren't a huge part of the story so players won't readily come by information about who they are or what they do, but the information is there to be sought out. Rattlers are heavily armored and use both humans and infected in sadistic ways. Infected are chained up around their camp almost like an alarm system, and humans they encounter who aren't members are captured and forced to perform slave labor. This unfortunate fate is what befalls Abby and Lev as they look for the Fireflies, and they almost catch Ellie in one of their traps as well.
Humans are treated so cruelly by the Rattlers that many try to escape just so they can commit suicide and avoid meeting their end on the pillars, tall beams set up by the beach where misbehaving slaves are strung up to die. When Ellie breaks into the Rattlers' camp and finds the prisoners, she's informed that Abby tried to escape and has been sent to the pillars. It's a horrible way to die, and upon finding Abby and Lev, it's clear that Rattlers take pleasure in starving and torturing their captives.
Sometimes, Rattlers will also intentionally infect their prisoners and chain them up to taunt them as they turn. Luckily for Ellie, they are a little too relaxed around infected, so when Ellie frees them, they are able to take revenge. If any group in The Last of Us 2 deserved to get caught between Ellie and her revenge, it's the Rattlers.
The Fireflies
The Fireflies are featured more prominently in The Last of Us, but they play a huge background role in The Last of Us 2 and could appear again in The Last of Us 3. Abby's father, Jerry Anderson, was the surgeon who was supposed to operate on Ellie in the original game. When players went back and experienced some of Abby's backstory, they were reintroduced to the Fireflies and their leader, Marlene.
The Fireflies are a militant group, who revolted against military oppression in Quarantine Zones. The group was larger and more organized than other factions and prioritized researching a vaccine that could potentially protect against the cordyceps brain infection. That dream died with Jerry Anderson, but towards the end of the game, Abby attempts to make contact with a surviving group of Fireflies. So, their future is uncertain.
If Abby and Lev made it to the Fireflies after the conclusion of The Last of Us 2, it's very likely that players will come across the faction again in The Last of Us 3 or in future DLCs. Even if they didn't make it, Ellie's path could take her back to them in future games. Overall, the Fireflies have an almost legendary presence in both The Last of Us and The Last of Us 2. The Firefly slogan, "Look for the light," was meant to inspire hope, but despite the faction's size, it has always felt elusive. The Fireflies represent something that people in The Last of Us 2 desperately want to believe in, but that isn't everything it promises to be in reality.
The Last of Us 2 is available now on PlayStation 4.