Singularity is the seventeenth and final main quest in Horizon Forbidden West.

Synopsis

After defeating Regalla's rebels at the Memorial Grove, Aloy returns to the Base, where Erend informs her of Sylens's arrival. She goes to confront him for betraying her at the HADES Proving Lab and warns him that further deceptions will result in his death. They are joined shortly after by Tilda. When she questions the functionality of Sylens's secret weapon, he sarcastically offers to test it on her. The two are locked in a bitter standoff until Aloy orders them both to stand down.

Aloy assembles her allies in the facility's Control Room, where Tilda briefs them on the plan to infiltrate the Zenith base and provides them with coordinates for a rendezvous point, a Campfire beneath the remains of a Horus titan on the Pacific coast. After sending everyone else off, Aloy entrusts Alva and Kotallo with a mission to destroy the Zenith base's regulator once they're in to help stop their drones, and then hacking into their network to search for any information about them that Tilda might be withholding.

Afterwards, Aloy travels to the rendezvous point and assembles her allies, where Tilda shows the way into the base: an abandoned tunnel that she had concealed from her fellow Zeniths. Once on the other side, Alva and Kotallo go off into their assigned mission, and Aloy instructs Zo (and depending on the player's choice, Regalla) to take high ground and provide covering fire if needed. Tilda and Sylens head for a nearby node in order to hack it and temporarily protect the others from detection. Tilda also temporarily opens up a virtual space for Beta so that she may communicate with Aloy, at the latter's request. Erend and Aloy make their way into the base through a series of gorges, engaging Specters several times along the way.

Arriving on a cliff near the Zenith launch tower, Aloy and Erend witness a swarm of countless Specters descend on the plains surrounding the base. HEPHAESTUS, having been secretly injected into the Zenith network by Beta, uses the base's printer (which is far faster and more efficient than any Cauldron) to churn out an army of the its most formidable Combat machines, namely Thunderjaws and Slaughterspines, that engages the Specter swarm. Aloy and her allies use this distraction to safely pass across to the launch tower.

The allies finally regroup on the approach to the tower. If Regalla was spared, she will stay behind to buy time for the others to escape when their way is intercepted by a Specter, but she is trapped behind falling rubble and killed when more Specters arrive and corner her.

At the base of the launch tower, the remaining Zeniths emerge and offer to spare the allies if they give up Tilda. Hearing no response, they open fire. Sylens throws his secret weapon in the Zeniths' direction, which activates after a short delay, disabling their shields. Gerard and Erik retreat back into the tower, with Tilda in pursuit, while the remaining Zeniths are picked off by HEPHAESTUS's machines.

The squad leaps into the battlefield, with Aloy making a run for the tower while the others stay behind and fight the last remaining Specters. However, just as she's about to use the elevator, Aloy is caught off-guard by Erik, who boasts that he doesn't need a shield to take her down before engaging her in combat. Aloy defeats the now-vulnerable Erik, and Zo arrives to finish the job by driving Varl's spear through his back, finally avenging her lover.

Aloy attempts to use the elevator again, but is informed by Tilda that Gerard has taken control of a number of the facility's systems and restricted access to the top, and she is forced to climb the rest of the way up. On her way up, Aloy is informed by Alva, who has successfully hacked into the Zenith network, that she found a lot of references to sometimes called "Nemesis" that the Zeniths were afraid of, as well as evidence that the Zeniths were preparing to leave Earth.

Once on the top, Aloy frees Beta from her constrains and asks for her help in looking through the Zeniths' files for information on Nemesis. Beta's search reveals an entity in deep space, resembling a vast swarm of machines with astronomical energy readings that is rapidly heading towards Earth, which she deduces must have destroyed the Zenith colony in the Sirius system. Aloy concludes that the Zeniths are on the run from the entity; Earth isn't a new home for them, but a mere way station. They are interrupted by Gerard being blasted into the room by Tilda, who finishes him off with a Plasma shot. When confronted by Aloy, she reveals the truth about Nemesis: a rogue AI, the result of a failed experiment, that had destroyed the Zeniths' colony in the Sirius system and sent the Extinction Signal that woke HADES to deny the survivors a viable home. Upon learning of HADES's failure, it launched itself towards Earth to finish the job itself. She invites Aloy to board the Odyssey together and bring GAIA with them to another world beyond the reach of Nemesis, leaving Earth doomed. When Aloy refuses, Tilda forms Specter Prime around herself and attempts to take her by force. However, Aloy prevails against the machine, killing Tilda in the process.

Sylens arrives, and reveals that he had known all along about Nemesis from his interrogation of HADES. Citing the impossible odds of survival against the rogue AI, he decides to board the shuttle and seize the Odyssey for himself, along with the APOLLO archive. Unlike Tilda's aggressive approach, he politely invites Aloy to to join him aboard the ship, arguing that by doing so, she wouldn't be abandoning life, but saving the seed for a new world. She refuses and bids him farewell as the rest of the squad arrives. Beta and Aloy share an intimate reunion. Seeing Aloy's friends firmly gathered around her, Sylens has a change of heart and climbs back down, having decided to stay on Earth for a while and help the tribal inhabitants prepare for the fight ahead. The others savor their moment of victory, gazing up at the night sky.

In the subsequent epilogue, Aloy sends her allies to spread knowledge of Nemesis across the known world, while Beta reinstalls GAIA at the Base.

Objectives

• Return to the Base
• Assemble Your Companions
• Talk to Your Companions (optional)
• Go to the Rendezvous Point
• Call Your Companions at the Campfire
• Go to the Launch Tower
• Go to the Top of the Tower
• Kill Erik
• Go to the Top of the Tower
• Defeat Tilda
• Return to the Control Center

Post-Quest Status Changes

Completing this quest completes the main storyline. In contrast to the ending of Horizon Zero Dawn, however, the game does not revert back to right before the final quest begins, but rather continues on. A few permanent status changes occur, however:

• Only Sylens, Beta and GAIA remain at the Base (with Beta now relocated to the main chamber). Kotallo relocates to the Memorial Grove, Zo to Plainsong, Alva to Legacy's Landfall and Erend to Hidden Ember. All can be located and conversed with about post-storyline events. Side quests related to the characters but not tied to the main storyline can also still be completed (though Aloy will have to travel to those settlements to complete/progress quests as applicable). Several points within the Base (and outside at Varl's grave) offer additional monologue opportunities.
  • However, if the player has the Burning Shores DLC installed, the conversation with Sylens in the Base becomes impossible to have as To the Burning Shores begins immediately after Singularity concludes, where Sylens is relocated to Tilda's Mansion as part of the quest. Notably, as having the game without the DLC is only possible on the PlayStation versions of Horizon Forbidden West, the conversation with Sylens is impossible to have on the PC version.
• A location for launching New Game+ is added to the Base, next to where Erend previously sat.
• Erend is no longer available as a Machine Strike player.
• The gallery and basement area of Tilda's Mansion become accessible again.

Glitches/Mistakes

When talking to Kotallo, he will remind Aloy about a plan to test his new arm on a Tremortusk and Aloy promises to meet him at a site. This exchange makes no sense, as they never planned to do so, and this test cannot actually be done.

When talking to Tilda, a dialogue option allows Aloy to listen again to why she created her house. However, Tilda uses the phrase "this house", despite not being in the house. Additionally, the subtitles read "that house".

After laying out her plan, a marker will be present above Aloy's companions' heads to indicate they have new dialogue. This will appear even if Aloy has already exhausted their dialogue before discussing the plan as there is no new dialogue unlocked by reaching this point.

Regalla will clip through the door leading into the tunnel to the Zenith Base.

During the battle between the Specters and HEPHAESTUS's machines, most of the machines' eyes aren't red.

Many of the Specters seen in the big battle have noticeably less detail than others. This was likely done on purpose to lessen strain on systems.

After the hangar collapsed with Regalla and several Specters inside, the subtitles do not appear when Zo says "May Regalla return to the cycle."

The plasma blast fired by Erik at Aloy during the cutscene is clearly aimed to low to hit her, but when the camera changes, it would've hit had she not dodged.

One of the unnamed Zeniths is firing plasma blasts from her hand without a Specter Gauntlet.

As the Dreadwing flies away with a Zenith, she briefly falls behind the Dreadwing before quickly moving back into its grab.

After Sylens removes the weapon from the device on Erend's back, the weapon is back on the device immediately after the weapon is triggered.

During the finale cutscene, one of the ships at Legacy's Landfall is shown leaving, and after the quest, Aloy mentions how most of the Quen have left to return home. Despite this, there are no noticeable changes to the settlement in terms of population, and of all the ships are still present at the dock.

After Zo shoots a Specter as Aloy runs ahead of her, the Specter next to the one shot is missing its cannons' arms.

During the battle against Specter Prime, the hologram of Nemesis is missing.

In one of the shots of Aloy and Sylens talking, the hologram of Nemesis is reflected in the table unrealistically.

As Aloy watches her team leaving the Base on Chargers, they are heading east. While this is the correct direction for Zo to arrive in Plainsong, it is the wrong direction for Kotallo to return to the Clan Lands, for Alva to return to Legacy's Landfall and for Erend to go to Hidden Ember.

After the credits, the icons for various locations flown over during the credits will flash on the screen one after another over several seconds, even if the credits were skipped.

Gallery

Screenshots