Buer had been about to call him back.
Ningguang stepped in front of the warning.
"Trust him," she said, without turning around. "He does not step into things he has no ground to stand on."
Buer held her silence. What she noticed, a moment later, was that the connection between herself and Irminsul , the thread that had always been present, steady as a heartbeat, her entire conscious life , had gone quiet the instant Ryen made contact with the tree. Not severed. Quiet. As though Irminsul had redirected its attention entirely to one point of contact and had nothing left over for anything else.
She could not intervene even if she wanted to.
There was nothing left to do except wait and watch.
Ryen stood with his hand flat against the bark of Irminsul and looked at it in the way he looked at things he found genuinely interesting: without hurry, without agenda, taking inventory.
The Forbidden Knowledge , which had recoiled from him at the moment of contact, pulling back from his hand like a cat touching something unexpectedly sharp , was now circling the area around his palm at a cautious distance. Not gone. Not attacking. Watching, in whatever way a force without eyes could be said to watch.
He found this interesting.
"Interesting."
The deep, old voice arrived in his mind before he had fully registered the transition , not loud, not intrusive, but present in the way that large things are present, filling the available space without effort.
Lord of the Outer Realms… please save me…
Ryen waited.
Lord of the Outer Realms… save me… save Teyvat…
The signal continued. He let it run.
Lord of the Outer Realms…
Lord of the Outer Realms…
After the fourth or fifth repetition, it had crossed from urgent to repetitive, and Ryen had had enough.
"Stop calling. I am here, aren't I? Keep this up and I will leave you to it."
Irminsul went instantly silent.
The quiet was immediate enough to be slightly undignified. Ryen noted this with the particular appreciation he reserved for things that were funny without meaning to be.
"Better. Now , I have questions, and you are going to answer them."
The great tree made a sound that was not a sound , a tremor in the bark against his palm, something between acknowledgement and bracing itself.
"First question. Do you have any record of my memories?"
"None." The response was immediate. "The memories of a Descender cannot be retained. The position of World Master places you above Teyvat's jurisdiction , nothing of you can be held here."
Exactly as expected.
"Second question. You called me the Lord of the Outer Realms. What outer realms , outer to Teyvat, or outer to the entire universe?"
Silence.
This silence was different from the obedient silence that had followed his threat. This one had texture. He could feel it , the quality of something large and ancient calculating whether it was safe to answer.
It was afraid.
He raised an eyebrow, reached into the space beside him, and drew out the Sword of Cosmic Dominion.
The blade did not flash. It did not radiate power for an audience. It was simply present , and for Irminsul, which had spent more centuries than it could easily count being unable to find anything that could help it, the presence of this particular object carried a quality of reassurance that registered immediately.
The trembling in the bark diminished.
"Beyond the Imaginary Tree and the Sea of Quanta," Irminsul said at last. "The Lord of the Outer Realms."
"As I suspected."
Ryen returned the sword to wherever it lived when he was not holding it.
He gave the tree a light pat, the way you might pat something that had just done something correctly despite clear reluctance. "You can say it. No one is going to come after you for telling me."
The next silence was shorter.
"Third question." His gaze moved to the mass of Forbidden Knowledge still drifting at the edges of his proximity, restless and uncertain. "Is this actually Forbidden Knowledge? Because it does not feel like a threat to me."
That was the precise truth. What he was feeling from the black mass was not menace , it was something he could only describe as urgency. A persistent, directionless pressure that kept nudging at the edge of his awareness, carrying the quality of something that wanted to be picked up and used. It reminded him of nothing so much as the feeling of encountering an element in a chemistry set that your teacher had labelled dangerous, and finding that your hands wanted to reach for it anyway.
The answer took longer than the others.
Irminsul was quiet for what might have been minutes. Ryen waited without impatience. In his experience, the most informative silences were the ones that something was working hard inside.
When the voice came back, it was in short pieces.
"For Teyvat , forbidden. For the universe , ultimate."
"What universe?"
"The universe of the Tree and the Sea."
"What tree? What sea?"
"The Imaginary Tree and the Sea of Quanta."
"And what exactly is this power?"
"…"
The rapid exchange stopped.
He had already assembled most of the answer in his mind. He simply needed Irminsul to confirm what he was already certain of.
"The power of order. Of the Imaginary. The force of the Void."
Ryen's eyes lit up.
The corner of his mouth, which he was not entirely in control of at that particular moment, moved upward without his authorisation.
Of course it is.
He had begun to suspect it the moment he first saw Buer's condition , the moment he understood what the Forbidden Knowledge truly was, and started turning over why it had the properties it had. The hypothesis had sat in the back of his mind through everything that had followed, and now Irminsul had just confirmed it.
The Forbidden Knowledge was not evil. It was not malicious in its nature. It was not a weapon aimed at Teyvat.
It was Imaginary Energy.
And the reason it had devastated Teyvat was not because it was inherently destructive , it was because Teyvat was not built to contain it. The world had encountered a force that belonged to a different order of magnitude and had responded the only way an unprepared world could: by breaking under the weight of something it was not equipped to hold.
He thought of the parallels. In the universe of the Tree and Sea, there were civilisations that treated Honkai Energy as an absolute interdiction , something that could not be touched without destruction, a law of nature as inviolable as gravity. And there were other civilisations that had learned to harvest it. That had built entire technological and military frameworks around it. That had risen to heights that the first category of civilisation could not conceive of precisely because they had looked at the thing labelled do not touch and decided the label was about capacity, not character.
The same force. Completely different outcomes. The variable was not the energy , it was who was holding it, and what they could hold.
Like a supplement, he thought. The kind that transformed a professional athlete into something more, and hospitalised someone who had never exercised a day in their life. Same substance. Different results depending entirely on the vessel.
Teyvat was a vessel that had not been ready. The Forbidden Knowledge had arrived before the world had built the infrastructure to receive it. Rather than advancement, it had produced the Withering, the Blight, five centuries of accumulated suffering , because that was what happened when you introduced terminal-level energy into a system operating at beginner capacity.
He had even briefly entertained the idea that this was Honkai Energy directly , the corrupting, consuming force that the HI3 universe knew as the Honkai. The grey-black scales of the Blight patients had reminded him uncomfortably of Honkai-corrupted soldiers in their early stages. But the comparison had not held up under examination. Honkai was not selective: it consumed everything , people, animals, monsters, land alike. The Blight had targeted only humans. Honkai-corrupted individuals eventually became something worse, something irreversible, something dangerous; Blight patients got worse and stopped. And Honkai, once it arrived in a world, did not wait a thousand years to finish destroying it. Rukkhadevata had managed to slow it, manage it, hold it in partial check for over a millennium , something that should have been completely impossible if this were genuine Honkai Energy.
That hypothesis had been discarded early. This was not Honkai.
Honkai and Imaginary Energy did share a common origin , the Imaginary Tree and Sea of Quanta in unending rivalry, the Honkai itself being the corrective mechanism born from that rivalry. Some resemblance between the two forces was natural. But they were not the same.
This was Imaginary Energy. The foundational force of the universe that housed Teyvat. The power of order, of creation, of time itself , the substance in the trunk of the Imaginary Tree from which all worlds were grown as branches.
And it had somehow come through the Abyss beneath Teyvat and into the world.
Which meant , he turned this thought carefully, making sure of the angle before he applied weight to it , the Abyss beneath Teyvat was not above the Sea of Quanta. It was adjacent to the Imaginary Tree itself.
He looked up at Irminsul.
"Teyvat exists on a branch of the Imaginary Tree," he said. Not a question, but he wanted confirmation. "And when King Deshret reached down into the Abyss, he did not find the Sea of Quanta at the bottom. He found the Imaginary Tree. Is that correct?"
A long pause.
"…Yes."
"And he brought back its power. The power of the Imaginary. The force that Teyvat could not contain."
"…Yes."
"Which eventually infected Rukkhadevata, who carried it into her connection with you, and through that connection corrupted you from the inside."
"…Yes."
He made a sound that was half acknowledgement, half something more complicated.
"You had the ability to warn Rukkhadevata. She could hear you, you could reach her. You could have told her to intercept Deshret before any of this began." He looked at the black mass still orbiting carefully around the perimeter of his reach. "But you didn't."
The silence that followed had something in it that he was not entirely sure Irminsul was capable of, but which resembled embarrassment.
"Because you thought," Ryen continued, with the particular tone of someone reading something they already know from a document they don't need, "that if you could absorb enough of this energy , if you could hold enough of the Imaginary Tree's fundamental power , you would gain something. Teyvat would gain something. A path toward a higher tier of existence."
"The essential nature of the World Tree is to accumulate memory, accumulate knowledge, and promote the evolution of its world."
"This is the World Tree's instinct."
He could not argue with that. Whatever else Irminsul was or had done, the drive behind the decision was not malicious. It was the decision of a system doing exactly what it was built to do, and gambling on a way to do it faster and further than it was designed to reach.
"That is true," he said. "And also a magnificent demonstration of overreach. There is ambition, and then there is reaching into the fundamental architecture of the universe with a world's hands and trying to eat what you find there."
He patted the bark again.
"You should count yourself fortunate the Imaginary Tree does not have consciousness to feel offended. And that Teyvat was not far enough along in its development cycle for the Honkai to show up in response." He paused. "If either of those conditions had been different, there would be no Teyvat to have this conversation in."
Irminsul had no answer for that.
"Right." Ryen rolled his neck slightly, thinking. "So. You want me to save you. And what you need saved from is Imaginary Energy that your own decision introduced into your system a thousand years ago, that has been eating you ever since."
"Lord of the Outer Realms… save me… save Teyvat…"
"I heard you the first six times. I'm thinking."
And he was.
Because here was the thing about Imaginary Energy: cutting it was an option. The Sword of Cosmic Dominion cut whatever existed in form, including laws and concepts. Imaginary Energy, concentrated into a form through Rukkhadevata's effort, had already been cut once. What remained in Irminsul could presumably be handled similarly.
But.
Imaginary Energy.
The fundamental force of the universe from which Teyvat's entire branch of existence had grown. The ubiquitous essence of existence, a cosmic structure that gives birth to many worlds, present in the trunk of the Imaginary Tree and flowing through every branch, every world, every civilisation that had ever drawn breath.
The probability of something like this landing in his hands, in a form he could actually interact with, if he went looking for it across all of time and all of the worlds available to him , essentially zero. This was the kind of thing that existed at the level of cosmological architecture. You did not encounter it. You certainly did not encounter a loose quantity of it, unmoored from its origin, sitting in a world tree waiting for someone who could approach it without immediately coming apart.
Cutting it felt, frankly, like a criminal waste.
The problem was that he was not sure he could absorb it. He was from outside the Tree-and-Sea universe entirely. The Imaginary Tree's laws were the laws of that universe, and those laws did not govern him , which was precisely why the Forbidden Knowledge had recoiled from him rather than consuming him. He could destroy what did not belong to his framework. He could not necessarily claim it.
He turned this over slowly, aware that the group behind him was beginning to wonder why he had gone quiet.
"Everything alright?" Ganyu's voice carried from the safe distance behind him.
He raised a hand without turning around.
"Fine. Working on something."
Something very important, he added internally. Specifically: how to steal a piece of the Imaginary Tree without technically stealing it.
"Lord of the Outer Realms," Irminsul said, with the cautious quality of something that has been quiet for a while and is not sure whether it has permission to speak.
"What?"
"Save me… please…"
"I said I'm thinking!"
The bark under his palm trembled apologetically.
He looked at the Forbidden Knowledge , the Imaginary Energy , drifting at the edge of his proximity, and let himself feel the quality of it more carefully than he had before. The urgency. The pull toward him. The way it had backed away from him when he first touched the tree, but had not left. The way it was circling rather than retreating.
The way it seemed, for lack of a better word, to be interested in him.
He thought about what Irminsul had said. World Master. Lord of the Outer Realms.
He thought about what the System had said, back in that first moment of contact.
A corrupted Irminsul , foundational structure of the world of Teyvat , has detected the host's identity. It has transmitted an appeal to the World Master.
He tipped his head slightly.
"You," he said quietly, to the drifting mass of Imaginary Energy. "You can feel what I am."
The mass did not respond. It had no voice. But it had not moved away.
"And what I am , where I am from , is outside the tree and outside the sea. Outside the entire framework you were born from."
He considered this carefully.
If the Imaginary Energy could not be absorbed into him through normal means , because he stood outside the laws that governed it , could it go the other direction? Could something from outside the framework be used as a container precisely because it was outside the framework? A vessel that the force could not dissolve, could not contaminate, could not overflow, because the vessel was not made of anything that belonged to the same system?
He was not certain of this. He was working at the edge of what he could confidently theorise.
But the sword could cut it. His body could not be touched by it. His world could contain it without corruption.
He thought of the Forbidden Knowledge sitting in Buer's body, harmless once she was in the MC World, unable to spread because the MC World had its own laws and the Imaginary Energy had no path through them.
He thought of the System , the thing that had sat in the space of his consciousness since the beginning, that had protected his soul from everything that had tried to reach it, that had been present in every confrontation and had never lost once.
He exhaled slowly.
This might work.
Or it might be one of the more ambitious decisions he had made in a while.
Both of those things could be true.
He raised his hand from the bark and turned back to face the group, who were watching him with a collective expression that contained several things at once.
"I have some good news," he said, "and one thing I need to think through."
A beat.
"The good news is that I understand what this actually is. The Forbidden Knowledge , it is not a curse, it is not a disease, and it is not some ancient malevolent power unique to Teyvat." He let that land. "It is Imaginary Energy. The fundamental force of this universe, the same force that flows through the Imaginary Tree and every world branch it has grown."
He looked at Buer.
"King Deshret did not find the Sea of Quanta beneath the Abyss. He found the root of the Imaginary Tree itself, and he brought back a piece of what he found. Teyvat could not hold it. It spread through you, through Irminsul, and expressed itself as everything you and everyone else has been trying to manage for the past thousand years."
"So the thing I need to think through," he continued, with the calmly interested expression of someone turning over an engineering problem,
"is how to absorb it into myself."
A long silence.
"I'm sorry." Ganyu's voice was very measured. "You want to do , what?"
"Absorb the Imaginary Energy into my body," Ryen repeated, as if this were a reasonable thing to say in any context, because he had decided it was.
The silence that followed had several distinct layers to it.