At this point, Lu Chen could barely recognize his own storage room. He looked around, eyes wide.
"What did you two do to my storage room?"
The place now resembled a mechanic's garage. Tools of all shapes and sizes hung on the walls, and various pieces of equipment—many of unknown purpose—were strewn across the floor. In one corner, Lu Chen even spotted an old engine Zhongli had picked up during a junk shop run, now piled carelessly among the clutter.
"Welcome to..." Nahida removed her helmet. "The secret lab of Ei and me."
"Lab?" Lu Chen glanced at the dim surroundings. He'd never seen a lab so... makeshift.
Ei looked at him seriously. "We're still unsure whether ambient light might interfere with the experiments, so we figured it was best to keep the door shut."
Lu Chen let out a small "oh," then closed the door behind him. Now, in the darkened room, the only source of illumination was a soft blue glow emanating from the workbench.
That pure, intense light flickered across the three of their faces, casting shifting shadows.
"This is what you extracted from the fragment?" Lu Chen asked.
Ei nodded. "Through analysis, we found a small crystal embedded within. It contains a very unique energy source—the blue glow you're seeing now."
Lu Chen stepped closer to the workbench. The black shard Ei had brought back was nowhere in sight. Instead, a transparent wide-mouthed jar sat on the table, the blue glow pulsing softly from within.
"What exactly is this?" He looked between his two "researchers."
Nahida's expression turned solemn. "This doesn't belong to the world of Teyvat. It's forbidden knowledge from the sky. Even after thousands of years, its energy hasn't dissipated. It can self-regulate, repair damaged structures, and naturally purify corruption."
Lu Chen nodded thoughtfully. "No wonder it looks so pure. Celestia's tech really is something else."
Ei narrowed her eyes slightly, carefully picking up the jar so Lu Chen could observe the mysterious energy up close.
"We believe this is a fundamental, Primordial Energy source. So we've named it 'Primordial Energy.'"
Noticing Lu Chen rubbing his chin in thought, Nahida added, "If you've ever seen the Scarlet King's kingdom in the desert, you'd understand this kind of energy. Those ancient machines, powered by Primordial Energy, still function perfectly even now. A power that approaches eternity... it can only have come from Celestia."
"This stuff's amazing," Lu Chen muttered. If time hadn't been so tight back then, he would've taken more from the Skyfrost Nail when he had the chance.
As the three of them discussed in the dark room, a curious voice suddenly called from the other side of the door.
"Huh? Lu Chen, Ei, Nahida?"
"What shady stuff are you three doing in there? Why's the door locked?"
It was Venti.
Lu Chen glanced at Nahida. Once she safely stored the blue energy and gave a nod, he opened the door.
Outside stood Venti and Zhongli, peering into the room with curiosity. Venti looked around, eyes shining with interest.
"What are you guys working on? Why didn't you call me if it's something fun?"
Zhongli, on the other hand, frowned slightly. "I'm sensing a strange energy. It's dangerous."
"Of course it is. It's forbidden knowledge, after all..." Lu Chen ushered the two inside and closed the door again.
With five people now crammed into the already crowded room, the atmosphere felt even tighter. In the dim glow of the single light source, five pairs of eyes exchanged silent glances.
Lu Chen made a face. Being squished into a tiny, dark room with these four… definitely felt weird.
After explaining the situation with the "Primordial Energy," their reactions varied.
Zhongli appeared concerned about the dangers of forbidden knowledge, while Venti was more intrigued—especially curious about how Ei and Nahida had managed to extract it.
"Forbidden knowledge is definitely dangerous..." Lu Chen said, gazing at the soft glow in the jar. "But at least this kind doesn't seem too bad."
Forbidden knowledge could be split into two categories: knowledge from the sky and knowledge from the Abyss. Also known respectively as "Sky Nail technology" and "Abyss technology," both were considered untouchable and unmentionable—knowledge so dangerous it could doom entire civilizations.
From Lu Chen's experience, the Abyss was far more chaotic and destructive. It brought pollution, madness, and corruption—once touched, it clung like a curse. That, he thought, was the true definition of "forbidden knowledge."
Abyssal power came from the Void, from beyond Teyvat. Fanes created the eggshell that sealed the world to prevent the Abyss from seeping in.
The one thing he forbade: the temptation of knowledge. But even so, the forbidden knowledge of the Abyss had enticed countless humans and led to endless ruin.
In contrast, the Sky Nail technology in front of them seemed much more agreeable. Celestia's tech was, at its core, advanced extraterrestrial technology. When science reached such heights, to a chaotic and primitive world, it would appear divine.
"So... you've already considered the risks?" Venti asked. Like Zhongli, he was a wily veteran—and no less wary of anything linked to Celestia.
Their discussion eventually led to mention of a now-deceased Archon, one who had taken the form of a great serpent.
Just knowing too much of Celestia's dark history had been enough for them to demand his death—and Ei had been the one to carry it out.
Now, the four gods found themselves huddled together in a small, dark room, trading tales of Celestia's hidden past. And yet, nothing happened.
"So don't worry!" Lu Chen shrugged. "If we were in Teyvat doing all this, Celestia would've already sent someone to eliminate us. But here? We've said and done so much—and not a thing has happened. That's proof enough that Heavenly Principles have no power in this world."
"That's a relief," Venti and Zhongli said, visibly relaxing.
"Nahida," Lu Chen asked, "do you think this energy could help contain the spread of The Withering?"
Nahida nodded. "Since this pure energy can suppress the power of the Abyss, it should logically be able to cleanse The Withering as well, since it's the Abyss' pollution manifest. We've already extracted a small amount. Lu Chen, would you help us run some experiments?"
"Sure," Lu Chen said. "What do you need me to do?"
At Nahida's prompting, he opened the news on his phone.
Lately, reports had been flooding in from all over—vegetation suddenly withering without warning. All signs pointed to The Withering.
Agricultural experts were growing alarmed. If this spread to farmlands, it would render soil infertile in an instant. Nothing would grow. And if it kept spreading? The consequences would be catastrophic...
Lu Chen located a newly reported outbreak site in the news. He nodded—and in the next moment, his figure vanished from the room.
...
Half an hour later, Lu Chen reappeared in the backyard, holding a faintly wriggling "Withering Tumor."