With the Crystal Core secured, the pieces for our desperate gambit began to fall into place. Lisa sequestered herself in her workshop, her usual languid demeanor replaced by a whirlwind of focused, manic energy. The library became a fortress of arcane science, its doors barred to all but Jean, who acted as her tireless quartermaster, procuring rare reagents and ancient texts. The air around the library hummed with a palpable power, a constant, low-level thrum of Electro and concentrated Anemo that made the hair on your arms stand on end if you got too close. Mondstadt had its weapon of hope, and Lisa was forging it with all the formidable skill she possessed.
While she toiled, my duty reverted to the shadows. Kaeya and I began the most dangerous and delicate phase of our operation: sustained surveillance of the Abyss Lector's ritual. Our goal was to map the rhythm of its dark hymn, to identify the precise moment of vulnerability Lisa had theorized. This was not a mission of daring infiltration, but one of infinite, nerve-shredding patience.
We established a series of hidden observation posts, or OPs, in the high ridges surrounding the camp. These were not comfortable blinds. They were cramped, cold hollows under tangled roots, or precarious perches on high, windswept ledges, each offering a different angle on the ritual site. We never used the same OP twice in a row, and our approach and retreat routes were randomized, meticulously planned to leave no trace.
My life fell into a grim, nocturnal rhythm. I would spend my days in a state of forced rest, my mind a quiet battlefield as I continuously suppressed the faint, lingering echoes of the Abyssal song. I would spar with Eula, my movements now so instinctual they required no conscious thought, my mind free to dissect the intelligence from the previous night. Her frustration with my seemingly effortless skill grew, but so did her determination. She had begun incorporating new techniques, seeking out old combat manuals from the library, her style becoming less predictable, more ferocious. Our rivalry was a strange, sharp comfort, a connection to a simpler world of tangible conflict.
Then, as dusk fell, I would meet Kaeya. We would slip out of the city like ghosts and spend the long, cold hours of the night crouched in the oppressive darkness, watching.
The vigil was a unique form of torture. We would lie motionless for hours on end, enduring biting winds and chilling dampness, our eyes fixed on the distant, sickly violet glow of the corrupted ley line. My attuned senses were both a blessing and a curse. I could feel the ebb and flow of the Lector's power with incredible clarity, but it also meant I was constantly subjected to its corrupting influence. I had to maintain a constant mental shield, a wall of will against the whispers of the Abyss, a process that left me psychically drained by the end of each watch.
Kaeya was the perfect partner for such a task. His patience was inhuman. He could remain perfectly still for hours, his gaze never wavering, his presence as unobtrusive as the stone he leaned against. He was a master of observation, noting every shift change of the Mitachurl guards, every flicker in the Abyss Mages' shields, every subtle change in the ritual's intensity. We communicated with a simple, silent language of hand signals we had developed. A raised finger: a change in patrol. A flat palm: power levels steady. A clenched fist: a surge in the ritual's energy.
It took four nights of this grueling surveillance before we found the pattern.
"There," I whispered, my voice a dry rasp. We were perched on a high, windswept rock face, the wind a constant, howling companion. I had the Resonance Tine—a new one, freshly created by Lisa—pressed against the stone, using the rock itself as a conductor to feel the vibrations from the ley line below.
For hours, the energy had been a sustained, high-frequency scream. But now, I felt it. A sudden, sharp dip. The overwhelming psychic pressure lessened for a moment, the roaring static in my mind dropping to a manageable hum.
"Pulse anchor incoming," I signaled to Kaeya.
We watched intently. The Abyss Lector, which had been chanting in a monotonous drone, raised its arms high. The violet light of the corrupted nexus intensified dramatically, flaring with a burst of pure, concentrated Abyssal power. The flare lasted for about ten seconds, and the psychic agony was so intense I had to bite my lip to keep from crying out. Then, as quickly as it came, the surge subsided.
And in its wake came the window.
The psychic pressure didn't just return to its previous level; it dropped significantly further. It was a moment of profound quiet, a silent pause in the unholy symphony. It was the moment the blacksmith's hammer was raised for the next strike. I could feel the corrupted ley line, its newly imprinted Abyssal signature 'unanchored', vulnerable, like soft, newly-worked clay before it is fired.
I held up my hand, my fingers spread, and began to count down the seconds with Kaeya. One… two… three… The silence was beautiful and terrifying. Ten… fifteen… twenty… At the twenty-five second mark, the Lector began to raise its arms again, preparing for the next anchoring pulse. At thirty seconds, the window slammed shut, the ambient psychic pressure returning to its oppressive norm.
We had it. Our window of opportunity. It was thirty seconds long, and it occurred approximately every three hours.
We spent another two nights confirming the pattern, ensuring its regularity. It was consistent. A rhythm of corruption. A rhythm we could exploit.
With our intelligence gathered, we returned to Lisa's workshop. The change in the room was astounding. What had been a cluttered space of theory was now a focused laboratory of creation. The Harmonic Resonator sat on the central workbench, nearly complete. It was a beautiful, intricate device, a sphere of polished silver and gold filigree centered around the brilliantly glowing Crystal Core I had retrieved. Delicate copper wires connected the core to a series of smaller, resonating crystals, each etched with complex runes. It looked less like a weapon and more like a celestial instrument.
Lisa, her hair slightly disheveled and dark circles under her eyes, looked at our data with a hungry, triumphant gleam. "Thirty seconds," she mused. "It's not much time, but it's more than I hoped for. It's enough." She made a final adjustment to the Resonator, and a pure, clean chime echoed through the workshop, a single note of perfect harmony that seemed to push back the very shadows in the room. "It's ready."
The final war council was convened. It was the four of us once again, gathered around the table in Varka's strategy room, the completed Harmonic Resonator sitting in the center like a sacred relic.
Kaeya laid out the final plan. It was audacious, bordering on suicidal. A five-person team. He would lead. He chose Roscher and Vile again, his two most trusted operatives from the 8th Company. He requested Jean, not for her administrative skill, but for her formidable combat prowess and her role as a symbol of the Knights' authority. Her defensive capabilities would be essential in holding the line.
And then there was me. My role was the most crucial, and the most dangerous. I would not be a primary combatant. I was the key.
"The moment we engage, the entire camp will descend on us," Kaeya explained, his voice low and steady. "Jean, Roscher, and Vile will form a defensive perimeter at the edge of the pit. They will hold the line. Their only job is to buy us thirty seconds of uninterrupted time. My job will be to get you to the ley line nexus." He looked at me, his gaze serious. "And your job, Arthur, is to place the device and activate it. Once that Resonator starts its purification hymn, all hell will break loose. The Lector will throw everything it has at you to stop it. You will be the single most important target on that battlefield."
"And our exit strategy?" Jean asked, her voice calm and professional, though I could see the tension in her hands.
"Is to survive," Kaeya replied bluntly. "Once the device is active, our mission is complete. We break contact and retreat to a pre-arranged extraction point, where a larger force of knights will be waiting to provide cover. But make no mistake," he said, his gaze sweeping over all of us. "The thirty seconds it takes to plant that device will be the longest thirty seconds of our lives."
The plan was set. The mission would take place the following night. As we left the meeting, a heavy, somber silence hung between us. We were no longer just friends or colleagues. We were soldiers on the eve of a battle that would determine the fate of our home, a battle no one else would ever know was fought.
I spent the rest of the day in quiet solitude. I didn't train my body; I honed my mind. I sat in my room, reliving the mission in my head, going over every step of Kaeya's plan, anticipating every possible thing that could go wrong. I strengthened the mental walls I used to shield myself from the Abyss, reinforcing my sense of self, my memories of my old life, my attachments to this new one. I thought of my parents, of Jean's unwavering sense of duty, of Eula's fierce determination, of Kaeya's cunning, of Lisa's genius. These were the anchors of my soul.
As dusk fell, I retrieved the two letters from my desk drawer. I read them over one last time. Then, with a steady hand, I lit a candle and burned them both, letting the ashes drift out my open window on the gentle evening breeze.
There was no room for contingency plans tonight. There was no fallback. There was only victory, or the end of everything I had come to love. I would not fail. I would not die. I would come back. It was no longer a hope. It was a promise.