The final days in Sumeru were a flurry of logistical triumph. The first order of business, before the final stamps could be put on Ren's stay in Sumeru, was the recovery of the Eclipsing Star.
For days, the sleek black hovercar had been missing. When Ningguang had arrived at the Sanctuary of Surasthana during the coup, the platform had been empty. At the time, with gods rising and mechs falling, a missing vehicle had been a low priority. But now, with peace restored, the Tianquan wanted her ride back.
It was Cyno who found it. Or rather, dragged the information out of a terrified, lower-ranking scholar who had been left behind in the purge.
"The basement," Cyno reported, his face impassive as he led them down a spiraling, dusty ramp beneath the Akademiya. "Azar had it moved. He claimed it was for 'safekeeping,' but the logs suggest he intended to have the Ksharewar sages dismantle it to study the engine once you were… dealt with."
They found the Eclipsing Star in a damp, dimly lit storage bay, sitting incongruously between crates of rejected thesis papers and broken Ruin Guard parts. It was dusty, but unharmed.
Ningguang ran a gloved hand over the hood, checking for scratches. "Petty," she murmured, her voice dripping with disdain. "To steal a guest's carriage while plotting treason… Azar lacked not only morals but dignity."
With the car recovered, the final hurdle was the hover vehicle review. Under the new administration—overseen by a reinstated and very cooperative Sage Naphis—the process was less of a trial and more of a formality.
Ren stood before the panel again. But this time, there were no trap questions, no accusations of sin. The scholars looked at him as peers. They asked about the power distribution metrics not to catch him in a lie, but because they genuinely wanted to understand how he had incorporated them here. He explained the gyroscopic stabilizers, the safety sensors, and the Mana-to-Thrust conversion ratios.
The stamp came down with a heavy, satisfying thud. Approved.
Ren walked out of the Akademiya with a sheaf of papers that legally bound the future of transportation to his name. He was done. His mission was complete.
And yet… as he packed his bags that evening, a strange, nagging sensation tugged at the corner of his mind.
He sat on the edge of his bed, staring at the photo album. He had pictures of everyone. He had patents. He had saved the city. But the story… the story felt unfinished.
He thought back to Lumine's words about the voice in the tree. "World… forget me."
He thought of Collei, cheerful but still bandaged, the shadow of Eleazar a constant threat despite the quell of the Withering. He thought of the Forbidden Knowledge that Dottore had tried to ignite.
The coup had removed the Sages. It had freed Nahida. But it hadn't cured the sickness at the root of the world. The Withering was suppressed, not gone. The Eleazar was halted, not healed.
There's one more thing, Ren realized, a cold shiver running down his spine. The original quest… it didn't end with curing the Forbidden Knowledge.
He laid down, the unease settling deep in his bones. He closed his eyes, focusing on the rhythmic breathing of Ningguang in the other room, trying to ground himself.
Sleep took him, but it was not a dark, restful void. It was a pull. A gentle, insistent tug on the silver thread that now connected his soul to the ley lines.
He opened his eyes.
He was standing on a surface of pink glass, surrounded by an endless sea of clouds and data streams. The air smelled of ozone and ancient memories.
Irminsul.
He walked forward. The tree was there, magnificent and glowing, no longer burning, but pulsating with a heavy, sorrowful light.
But he wasn't alone.
At the base of the tree, two figures stood.
One was small, dressed in green and white—Nahida. She was weeping, her small shoulders shaking with a grief so profound it seemed to vibrate through the dreamscape.
The other figure was… beautiful. She looked like Nahida, but grown. She was tall, with long, flowing white hair that faded into twilight hues. She wore robes that seemed woven from the light of the moon and the leaves of the forest.
Greater Lord Rukkhadevata. The former Dendro Archon. The one who had died in the Cataclysm five hundred years ago.
Ren approached slowly, feeling like an intruder on a sacred moment, yet knowing he was meant to be here.
Nahida was hugging the woman's waist, clinging to her as if letting go would mean the end of the world.
"Do we… do we really have to?" Nahida sobbed, her voice sounding so young, so heartbroken. "I just found you. I finally get to know you. I don't want to forget."
Rukkhadevata smiled, a sad, tender expression. She knelt down, bringing herself to Nahida's eye level. She wiped a tear from the smaller god's cheek.
"We must, my little moon," Rukkhadevata said, her voice like wind chiming through leaves. "It is the only way."
She looked up, her eyes—identical to Nahida's, yet filled with eons of memory—locking onto Ren. She didn't look surprised to see him. She looked… grateful.
Ren stopped a few feet away.
"You are the Anomaly," Rukkhadevata said gently. "The child touched by Time."
She stood up, keeping one hand behind Nahida's head. She beckoned Ren closer.
"Come," she said.
Ren walked forward. Rukkhadevata reached out and placed her other hand on his head. Her touch was weightless, like sunlight.
"You perceive the world differently," she murmured. "You know things that have not been written. That is why you are here. To witness."
She looked back at the tree. "The Forbidden Knowledge… it is not a poison that can be cut out. It is a part of me. Five hundred years ago, when I tried to save the tree, I was corrupted. My consciousness… my very existence… is tied to that corruption."
She looked down at Nahida, her expression filled with infinite love and infinite pain. "As long as I exist… as long as people remember me… the Forbidden Knowledge will remain. It will remain in the Irminsul, in the memories of the world. The Withering will return. The Eleazar will never truly fade."
Ren understood. To cure the world, the source of the sickness had to be removed. And the source was her memory.
"The world must forget me," Rukkhadevata whispered. "Completely. Every book, every stone carving, every memory in every mind… it must all be erased. Only then can the Irminsul be healed."
"But that's so sad," Ren whispered, his own eyes filling with tears. "To save everyone… you have to be erased? Like you never existed?"
"It is a price I pay gladly," she said. "For the future. For her. I was going to do this the last time you two were here, but with the Doctor here, I chose not to reveal myself."
She turned fully to Nahida. The little Archon was trembling, fighting against the inevitable.
"You are the moon," Rukkhadevata said softly. "And I am the sun. But the sun must set for the moon to shine. You have grown so strong, Buer. You have found friends. You have found wisdom."
She leaned forward and kissed Nahida on the cheek. It was a gesture of pure, maternal love, a transfer of hope from the past to the present.
"Do not be afraid," she whispered against Nahida's ear. "Wisdom is not about holding on. It is about knowing when to let go."
She stood up, stepping back towards the tree. Her form began to glow, dissolving into particles of pure light.
"Thank you, Ren," she said, her voice fading, becoming part of the air. "For helping her. For being the friend she needed. Watch over her."
"I will," Ren choked out.
Nahida reached out, her hand grasping at the light, but her fingers closed on empty air.
"Goodbye," Rukkhadevata's voice echoed one last time, filled with peace. "Nahida."
She turned into a million glowing leaves, swirling up into the branches of the Irminsul.
And then, the change began.
A wave of energy, invisible but palpable, exploded from the tree. It was a rewrite. A ripple in reality. It washed over the dreamscape, moving outward, preparing to wash over Teyvat.
It was the wave of forgetting. It was rewriting history, removing the name "Rukkhadevata" from every book, every mind, every stone.
Nahida stood there, her arm still outstretched, tears streaming down her face. But her eyes… they were glazing over. The confusion was setting in. She was the avatar of Irminsul, and even she was subject to the rewrite. She was forgetting the person she was crying for.
Ren moved.
He didn't try to stop it. He couldn't. This was necessary. This was the cure.
Instead, he stepped forward and wrapped his arms around the small, trembling god. He hugged her tight, grounding her in the moment, shielding her not from the wave, but from the loneliness of it.
"It's okay," he whispered, holding her close. "It's okay, Nahida. You did it. She loves you. She loves you so much."
Nahida clung to him, burying her face in his chest. "I feel… so sad," she sobbed, her voice confused, the name of the person she lost already fading from her tongue. "I don't know why… but I feel like I've lost something important."
"You saved the world," Ren said, tears running down his own cheeks. "And she… she cares for you. As well as Sumeru."
In the new history, there was no Greater Lord Rukkhadevata. There was only the current Dendro Archon, who had lost her power and reverted to a child-like form five hundred years ago.
But Ren… Ren was an anomaly. He was someone who was an affront to this world.
The wave must have passed over him, and yet he still remembered the name Rukkhadevata and the lore behind it.
He held Nahida as the light faded. He knew that he was the only person, other than Lumine being a descender, who would remember the name of the god who had just sacrificed her very existence to save it.
He stayed silent, holding the weeping Archon, as the dream began to fade, replaced by the deep, heavy silence of a world that had been healed, at the cost of a memory.