The last mission of H3 starts like this:
Aloy and her army arrive from the North into the desert Tenakth. To the West, 950,000 Carja march led by Nemesis in the form of Jiran, with Thunder jaws, Tremor Tusks, and Black Wings at their side, and many are mounted upon Clawstriders, Striders, and Sunwings. To the South, 300,000 Oseram, and 700,000 Carja, brought hoards of Machines at their side rally to the main Carja army. To the West, 4 million Quen come, ready to face the Carja.
"Surrender! For this continent is ours!" Roars the Oseram General at Jiran's side. The Quen exchanges looks, before their leader laughed: "What are you, before the chosen people? Drunks and weak silk wearers, who languish and grovel beneath a light in the sky! We are the chosen people, and not even your machines can protect you!"
Jiran stepped in front, "Chosen? You don't know what chosen means. Let me educate you..." he signaled to the Oseram General, who fired an arrow into the chest of a Quen soldier carrying a banner. The Quen leader turned to the soldier, who, after making a gutteral choke followed by a cough of blood, collapsed to the ground. Then he turned towards Aloy's army. "Have you Barbarians come to kill us, or to kill our enemies?" "Both" said Aloy, "If we have to." Jiran faced her, "I shall be the one to kill you!"
Then the three armies clashed, cutting each other down. Jiran wears Royal Carja armor, and despite doing and receiving lots of damage, fights like a normal human. During the Boss fight, the Eclipse theme song plays. Jiran's armorless after the fight. "Heh heh... Do you think that this can kill me?" He rises up, skin turning gray, eyes turning black, and slams the ground, sending out a massive shock wave. He does more damage during and attacks faster, but has much lower health during this phase. However, he is supported by 2 Oseram generals, a few Carja, and a Clawstrider.
After the boss, Aloy kills Jiran by stabbing him in the chest. The Carja look on in shock. But then, he rises up, ripping the spear outta his chest. He punches Aloy, launching her into the charred ruins of Thornmarsh. The trees are now burnt stumps, and thousands of Lowland Tenakth are crucified upon wooden x’s. In the background, a field is littered with dead Carja, and severely wounded Quen. A great Quen armada docks at the beaches, raining clouds of arrows upon the Carja. Nemesis leaps over towards Aloy, picking her up and throwing her into the Emperor’s ship. Aloy must then fight the Quen soldiers until she finds Alva, standing before the Quen Emperor. “Aloy is here to help us.” she pleads. But the Quen Emperor kicks her into the water.
Nemesis jumps to him, and gouges his eyes out. “Chosen people my ass!” He says, before throwing him hundreds of miles into the Ocean. He transforms into a Deathbringer equivalent of a Specter. During this fight, he has much more health than a Deathbringer, and’s a lot faster. After the fight’s over, he transforms back into a human, and punches Aloy through a mountain into the Bulwark. There, he transforms into a black Specter Prime, with a giant red laser sword. Aloy accesses her focus, “alright, Imma need a suit.” Gaia sends a Specter Prime Suit to Aloy, and with an epic remaster of Aloy’s Theme Song Playing in the background, Aloy and Nemesis have a Mech-Fight. After being defeated yet again, Nemesis rises, “D.C, ours, Ottawa, ours, Beijing, ours, Moscow, ours. We just need a few more major world Capitals, and I can fully conquer this world, a new world. A perfect world, where I’m the King, where I’m the GOD!”
His body forms into a Nano Tech Metal Devil, the size of the No Man’s Land. This is there’s two different options for endings. See which one you like more.
1: Aloy Dies
Knowing there’s no other way to stop him, Aloy goes into the Odyssey, filling it with explosives. Then she flies into the core of Nemesis’ true form, launching all of the Odyssey's firepower before crashing into his core, blowing him up, and creating a gigantic explosion. The screen cuts to all of the moments we’ve had with Aloy over the years, making a very sad ending. We’re fast-forwarded to Plainsong 19 years later, and play as Zo’s child, similar to Rdr2.
2: Sylens Dies
Sylens makes a heroic sacrifice, and we play an ending more similar to HFW’s ending.