Song of the Welkin Moon

A strange mechanical girl washes ashore in Natlan, clutching a cryptex addressed to the Traveler and Paimon. She is Ineffa, an amnesiac automaton from the far-off land of Nod-Krai, built by the tinkerer Aino around a salvaged Secret Source core. With help from Chasca, Ifa, Kinich, and Xilonen, the Traveler learns her core once belonged to the Eighth of the Thirteen Sovereign Lords — an ancient artificial intelligence executed by her peers for loving humanity, who split herself in two rather than choose revenge.

Ineffa's malfunctions lead the group into a buried Secret Source facility, where the truth turns lethal: the voice haunting her is the malevolent Eleventh Lord, who orchestrated everything to reclaim the Eighth Lord's core and bury humanity's champions underground. Ineffa shatters the stolen core to save her friends, then forges a new one of her own — awakening an Electro Vision built on a "Moon Wheel," a power tied to Nod-Krai's moon.

With the Eleventh Lord destroyed, the cryptex finally opens: a letter from Varka, Grand Master of Mondstadt's Knights of Favonius, thanking the Traveler and inviting them to meet him at The Flagship tavern in Nod-Krai — a treacherous land of feuding factions, Fatui schemes, and lunar mysteries. Ineffa promises to guide them there when they are ready.

Sailing with Ineffa to Nasha Town, the Traveler senses a familiar power the moment they step ashore: Kuuvahki, the primordial lunar energy of Nod-Krai — the same presence they felt when they first landed on Teyvat. Convinced their long-lost spaceship crashed somewhere in these islands, they explore a land caught between factions: Aino's workshop, the Ratnik Flins who guards the graveyards against the deadly Wild Hunt, and the Frostmoon Scions led by the moonchanter Lauma.

Nod-Krai's tensions sharpen quickly. The Fatui's Kuuvahki Experimental Design Bureau has pulled down pieces of the shattered Eternal Moon, and the Harbinger Sandrone personally warns the Traveler not to interfere. Lauma reveals her people's history: of Teyvat's Three Moons, only the Frost Moon survived the war against the Descenders, and prophecy foretold their goddess Kuutar's return — a return the Scions now suspect has come in the form of the Fatui Harbinger Columbina, the "Damselette." When Fatui soldiers deliver an ultimatum demanding the Scions' relic, the Moon Marrow, and their Kuutar, Lauma refuses.

That sleepless night, the Traveler follows a Luonnotar spirit into a flower-filled cavern beneath Hiisi Island and comes face to face with the sought-after Moon Maiden herself — a quiet, closed-eyed girl who is neither quite goddess nor quite Harbinger.

The Wild Hunt grows bolder, and a phantom stalks its attacks. While Aino repairs her Boom and Blast Kuuvahki Cannon, the Traveler works the town for information — mixing drinks at a clandestine Banquet with Nefer, the shrewd owner of the Curatorium of Secrets, and her clumsy assistant Jahoda. Columbina, weakened and hiding from the Fatui, reveals the enemy's identity: Rerir, one of the Five Sinners of Khaenri'ah, the moon-obsessed "Rächer of Solnari" who fell into the moon's reflection and now commands the Wild Hunt.

Then the Lightkeeper Sousi is found murdered, and a witness names Flins as the killer. The Traveler rescues Flins from Rerir's ambush and proves his innocence: the "Sousi" seen before the murder was Rerir wearing his shape. Flins — a centuries-old lantern fae who once lost his heart to humanity — swears vengeance for his friend.

Rerir's true scheme unfolds: he manipulates Nasha Town into firing Aino's cannon at him, converting its concentrated Kuuvahki through his Abyssal power to rebuild his body. Despite the Traveler, Flins, and Ineffa deflecting much of the blast, the Sinner regains physical form — incomplete, but strong enough to hunt the one being whose power rivals the moons': Columbina.

Rerir strikes at Columbina directly, overpowering her defenders; she burns the last of her strength teleporting the Traveler's group to safety. On the run from the Wild Hunt, they are rescued by Varka, Grand Master of the Knights of Favonius, who shelters them in his secret base. There Columbina proposes her countermove: gather all three Moon Marrows — relics of the dead moon goddesses — to restore her power. Nefer's intelligence network is reluctantly hired to help.

The hunt splits the group. At the Fatui Design Bureau, Sandrone grudgingly aids Columbina's escape when the Wild Hunt attacks; Nefer, Lauma, and Jahoda peer into fragments of Rerir's heart and glimpse his past as King Irmin's assassin, secretly engaged to a woman named Tholindis. Cornered at Thunderclap Reef, the Traveler and Columbina are saved by Arlecchino, who reveals herself a descendant of the Crimson Moon dynasty.

Arlecchino opens the way to the lost Iridescent Marrow, forcing back the Abyss at the cost of corrupting her own hands. With all three Marrows gathered, Columbina stands ready — while the buried history of Khaenri'ah, the "nation that doesn't exist," draws ever closer to the surface.

Reinforcements gather at Varka's base: the alchemist Albedo with a human-formed Durin, and — to everyone's surprise — Dainsleif, who wants Rerir's past investigated. Through Nefer's rituals, the group relives it: Rerir was King Irmin's blade, ordered to purge descendants of the Crimson Moon dynasty, until the day his target list named his own fiancée, Tholindis. Later, he joined Dainsleif, Surtalogi, Rhinedottir, and Hroptatyr in freeing the imprisoned seer Vedrfolnir — only to find Tholindis stepping into a portal to spare him, a loss that drove him to accept the Abyss's whisper and become a Sinner.

The ritual turns on its casters: Rerir traps them in a vision of Nefer's own past — her desert childhood, her tribe's annihilation, her bitter road through the Akademiya — and nearly kills her for prying before an unseen force scatters the dream.

With Rerir temporarily sealed in Nefer's chessbox, the group prepares a decisive battle. As the Sinner breaks free, Albedo and Durin siphon his power into Columbina through an alchemical array; the restored Moon Goddess overpowers him and opens a moon gate, and Dainsleif holds it wide as Rerir is hurled out of Teyvat entirely. Nefer pays for the victory with her eyesight — temporarily — and Nod-Krai breathes again.

Two months on, Nod-Krai prepares for Moon-Prayer Night, its greatest festival — and Columbina's farewell. Drained by the battle with Rerir, she must return to the moon when Kuuvahki peaks, or slowly cease to exist. Meanwhile, uncanny phantoms bloom across the land: untouchable replays of fixed history, from ancient Hyperborean scenes to visions of the cataclysm — among them a phantom of the Traveler's crashed spaceship at Starsand Shoal. Durin, forced to relive deaths he cannot prevent, wrestles with his Abyssal nature and chooses to seek truth anyway.

Then Columbina vanishes. The witch Alice appears in person with a devastating diagnosis: with all three moons' power gathered in Nod-Krai, Teyvat's border is destabilizing — and Columbina is not gone but fading from existence, rejected by the world because she has no true name and no anchor. Her Moon Marrow plan is already obsolete.

Alice sets two tasks: find Columbina's true name, and build a ritual gateway to send her home, with help from her fellow Hexenzirkel witch Nicole. Only the Traveler, Lauma, and Arlecchino prove compatible with the Kuuvahki infusion needed to enter the Hyperborean ruins. As the gate opens, Columbina — now an unseen, dwindling consciousness drifting through the festival preparations — realizes she may not survive until Moon-Prayer Night.

Deep in the Hyperborean ruins, murals reveal the full story of the Three Moons: created by Nibelung, weaponized in his war against the Heavenly Principles, then shattered or cast away until their goddesses died. The searchers find the ancient lunar-communication platform — but no trace of Columbina's true name, because she never had one. Nicole realizes a name need not come from the past: the Traveler calls out "Columbina," the name her friends gave meaning to, and it anchors her. Restored, she names herself in full: Columbina Hyposelenia, "born beneath the moon."

Nasha Town transforms Moon-Prayer Night into a homecoming for its Moon Goddess. Columbina spends the festival not as a god but as a friend — trading candy and games with townsfolk and Fatui alike, sharing goodbyes with Flins, Nicole, Alice, and even a reluctantly tender Sandrone — before hanging her wish: that all who dwell under the moon find belonging.

At the ritual site, betrayal strikes. Dottore, who has manipulated the phantoms' history to forge a false moon, ambushes the departure, freezing time to seize the power of all three moons. To deny him, Columbina abandons her homecoming and leaps into a moon gate of her own making, vanishing into the same unknown that swallowed Rerir. The shaken allies — Arlecchino foremost — vow to bring her back and stop the Doctor.

Guided by a Fatui messenger, the Traveler's group storms Dottore's arctic laboratory alongside Arlecchino and Sandrone, learning en route that the Doctor has built an artificial Moon Marrow. The confrontation is a disaster: armed with his creation, Dottore shrugs off their combined assault, teleports the group away, and takes the Traveler captive — courting them, in his twisted way, as a potential collaborator against the gods' rules.

In the moon's reflection, Columbina survives. Exploring memories that bend to her touch, she discovers the space flows backward through time — and that Dottore resurrected Rerir precisely to coincide with her weakness. Meanwhile Dottore hangs his false moon in Teyvat's sky in place of the Frost Moon, seeds energy anomalies across Nod-Krai, and curses everyone who entered his lab so they cannot leave the region.

The allies organize a total evacuation of Nod-Krai — Lauma and the Scions shepherding refugees toward Natlan, Arlecchino's Fatui escorting others into Snezhnaya, Durin and Dori carrying word to Venti and Nahida — while Sandrone shelters the displaced and Nicole hands out Dodocommunication Devices. As the false moon rises, the fight for Nod-Krai's fate, and for the captive Traveler, has already begun.

The Traveler rejects Dottore's pact and is rescued from his realm by the Wanderer, who forgoes his own revenge to do it. In the moon's reflection, Columbina meets a lucid Rerir and the soul of Tholindis, carries words of forgiveness between them, and walks backward through time to the imprisoned Three Moon sisters — Aria, Canon, and Sonnet. Learning of their fate, the sisters bequeath her their authorities: Columbina will "die" in the past, dispersing herself into Nod-Krai's moonlight, to be reassembled in the present by her friends' signal.

Everything converges on one desperate formula. The Wanderer wires his Irminsul core into Sandrone's world-calculation; Nefer risks blindness reading Columbina's plan from Luonnotar's memory. Dottore, transformed into the "Heretic of the False Moon," besieges Nasha Town and batters the defenders — and when Sandrone shields the Traveler from his killing blow, he executes her. Her formula stalls at ninety percent.

But the last ten percent was always the moon itself. Arlecchino, Varka, and Nicole tear the Frost Moon down through the false sky; Columbina's spirit and scattered light merge with the Trilunar Authority, and the Trilune Goddess opens her eyes for the first time. Together she and the Traveler shatter Dottore's artificial Marrow and vaporize him. Victory won, Columbina cradles Sandrone's body — the friend who never learned to say what she wanted.

A letter from Collei summons the Traveler to Sumeru: warned by a prophetic dream Nicole planted, Nahida has ordered the rainforest evacuated. Something is strangling Irminsul, blocking the Ley Lines from recording the world — and where the anomaly spreads, people's memories and minds unravel into madness. Nahida takes Irminsul's functions upon herself until she collapses, comatose, while a hooded Fatui commander moves detachments through the desert on behalf of a dead "client": Dottore.

The response is a nation-wide scramble. The Traveler carries Nahida to the Dendro Sovereign Apep, who shelters and restores her; the sages plan to restart the Akasha System to cleanse Irminsul; and in the desert, the Jinn rise in storms until the freed Liloupar pacifies them. Collei alone can command the Jinn with Nabu Malikata's prayer — a clue to the goddess remains Dottore once implanted in Nicole, now revealed as the Flower Goddess's.

With Sumeru sealed off from the world by its own defensive barrier, Nicole and Nefer slip in to help. At the Mausoleum of King Deshret, Nefer's answer — "time" — frees the Pillars Thoth, Heryshaf, and Sobek, and the Seven Pillars agree to open Aaru, the desert's realm of souls, as humanity's fallback: a new vessel for the world's memory as the catastrophe in dreams descends.

The enemy has a face at last: a surviving segment of Dottore entered Irminsul through death itself, and a monstrous Irminsul tree now towers over Sumeru City — the next stage of his deranged bid for godhood, bankrolled and abetted by the Ninth Harbinger, Pantalone. Kaveh and Alhaitham re-engineer Aaru into a replacement archive for the world's information, while Nahida arranges an unrecordable meeting: through the Traveler, she asks Mavuika for the Pyro Gnosis outright, and Natlan's Archon gives it freely.

The counterattack overloads Irminsul through the Akasha, then splits: Cyno's desert fighters draw off the Fatui while the Traveler and Wanderer infiltrate the Divine Tree. Inside Irminsul, Dottore taunts the Wanderer with his erased past as Scaramouche, but the pair hold him until Nahida — granted leave by the Shades Ronova, Istaroth, and Naberius — ignites the Pyro Gnosis and burns the corrupted world-tree to its roots. Dottore's own segments drag him into the flames; dying, he bids farewell to Pantalone, whose parting gift was one final backup planted in the Ley Lines.

Aaru quietly assumes Irminsul's role, Sumeru rebuilds, and Collei is promoted to Forest Ranger. The chapter that began beneath Nod-Krai's moon ends where wisdom was born — with the truth, at last, written on new pages.