Hotaru fell silent again.
That hesitation and unease almost materialized into energy fluctuations, forming subtle eddies around the ice crystal.
She was afraid of being used again.
Afraid that this powerful, cold-auraed swordsman in front of her would, like Muzan, view her and her sister as mere tools and test subjects.
She was even more afraid that agreeing to any conditions would shatter the delicate balance they currently held, disturbing her sister's painful slumber.
Just as she was indecisive, her heart struggling fiercely—
Om… an extremely faint ripple of energy emanated from deep within the gigantic, ethereal blue ice crystal.
The chill seemed to momentarily waver, and the energy, sealed for an unknown number of years, showed a nearly imperceptible fluctuation.
Cheng Mo's Eye of Truth instantly captured this subtle change.
"Energy frequency change… originating from the core… is the consciousness of the dormant entity stimulated by external information?"
He could "see" the change, but he couldn't interpret the deeper conscious activity behind this fluctuation, unlike how he deciphered energy flows.
But this fluctuation meant something entirely different to Hotaru.
"Sister?!"
Hotaru's voice exclaimed in Cheng Mo's mind, filled with worry and a faint hint of surprise.
"Sister… can you… feel it too? Can you… hear me?"
The fluctuation quickly subsided, returning to a deathly silence.
It was as if Yuki's consciousness had merely shifted inadvertently in her sleep.
But this brief anomaly made Hotaru realize that her sister might not be entirely lost in an unconscious, eternal slumber.
Deep within her consciousness, there might still be a faint connection to the outside world.
This both unsettled her, fearing that external communication would disturb her sister, and ignited a tiny, distant hope in her heart.
Perhaps her sister didn't want to sleep completely alone either.
Cheng Mo keenly noticed the subtle shift in Hotaru's emotions.
He didn't seize the opportunity to exert pressure; instead, he took a slight step back, showing he posed no immediate threat.
"I understand your concerns."
His tone remained steady.
"Unfamiliar power always comes with risks. You can take your time to consider; there's no need to make an immediate decision."
"I will stay in this vicinity for a while. If you change your mind, or… if the seal shows any abnormal fluctuations you don't understand, you can contact me through this mark."
As he spoke, he raised his hand, and a trace of extremely pure Lightning Release Chakra condensed at his fingertips.
It wasn't for attack, but to shape it into a stable and hidden runic mark, which he gently pressed onto the rock wall inside the cave entrance.
The mark flickered with a faint blue light, then disappeared, leaving only an extremely subtle energy trace.
"Activate it, and I will sense it," Cheng Mo said at last.
He did not forcefully break open the ice crystal.
That could lead to unpredictable consequences, possibly even destroying this valuable sample.
Cheng Mo chose more cautious observation and waiting, which itself reflected his Pay attention to of this special "case."
Having done all this, he said no more and turned to leave the cold cave.
He left the power of choice to the sisters, who were deeply mired in suffering and seals.
Stepping out of the cave, the cold night wind brushed against his face.
Cheng Mo's face was expressionless, but his eyes were deeper than usual.
He was clearly thinking rapidly about the possibilities of dual-soul symbiosis, soul seals, and the deeper mysteries of Muzan's blood.
Kuroba stood on his shoulder.
Through the soul link enhanced by the myriad realms compass, it could clearly feel Cheng Mo's deep thoughts at this moment.
It hesitated for a moment, its crow's beak opening and closing, and finally spoke: "My Lord…"
That low, captivating voice broke the silence of the mountain forest.
Cheng Mo stopped and looked at it.
Kuroba seemed to be organizing its words, finally saying: "If you wish to research soul-level powers, I have some information about the Ubuyashiki Family that might be useful to you."
Cheng Mo's heart stirred slightly.
As expected of the myriad realms compass's soul contract, it directly altered Kuroba's underlying logic.
He knew clearly that even if Kuroba was now one hundred percent loyal to him, in the absence of his explicit command or inquiry… based on Kuroba's past loyalty and habit of secrecy regarding the Ubuyashiki Family, it could have remained silent.
Yet now, it had proactively offered help.
This was undoubtedly the absolute sense of belonging brought by the soul contract, surpassing previous understanding, at work.
"Speak," Cheng Mo said concisely.
Having received permission, Kuroba seemed to relax a little.
It continued: "According to some secret traditions passed down through the Ubuyashiki Family… in this world, gods exist."
Cheng Mo's eyes narrowed, but then he relaxed.
Given that heaven and hell, and soul transmigration exist, the presence of so-called gods seemed unsurprising.
Kuroba continued: "Of course, rather than gods with specific forms, it's more like a certain… will of rules that maintains the world's operation, also known as 'Heaven' or 'Heaven's Will.'"
Its tone grew somewhat heavy: "And the Ubuyashiki Clan, because the Demon King—Kibutsuji Muzan—was born from it, Heaven cast a curse. The Ubuyashiki Clan cannot bear healthy male children; even if a boy is born, he will surely be sickly and die young."
"Later, the High Priest, a leader of shrine maidens with powerful spiritual energy, suggested that the Ubuyashiki Family intermarry with the 'Priestess Clan,' who had served the gods for generations, and that this lineage should continue for generations."
"Only in this way could they use the pure spiritual power of the Priestess Clan to offset some of the curse's erosion, allowing the male children of the Ubuyashiki Clan to not die young, and barely extend their lifespans."
Kuroba paused, then added: "The Priestess Clan is born with spiritual power, capable of communicating with nature and purifying defilement… their nature is very similar to the family of the self-sealed shrine maiden you just encountered, Master."
Cheng Mo listened quietly.
This information began to align with the original setting he knew.
It explained many reasons why the head of the Ubuyashiki Family was always sickly, and why their family was so deeply involved with Shintoism.
"However…"
Kuroba's tone shifted: "Even so, as more and more demons appeared in the world, and Muzan's harm to the world grew, that curse originating from 'Heaven' also seemed to be constantly intensifying."
"Even with intermarriage with the Priestess Clan, the lifespan of Ubuyashiki Family males remained short. Thus, an internal family rule of early and frequent childbirth was established to ensure the continuation of the lineage."
"And…" Kuroba's voice lowered slightly: "The family also secretly developed a 'Heaven-Deceiving Technique.' The Ubuyashiki Clan would raise their male children from a young age as if they were girls, using this method to deceive Heaven's perception, attempting to evade the most violent period of the curse during childhood."
A flash of understanding crossed Cheng Mo's eyes.
These details were briefly mentioned in the original work.
Kagaya Ubuyashiki's somewhat neutral, even slightly effeminate handsome demeanor was not innate, but a result of this cruel survival strategy.
Kuroba's tone carried a strange sense of emotion: "After nearly a thousand years of struggle and research, the high-ranking members of the Ubuyashiki Clan gradually realized that the so-called 'curse' was not merely a physiological disease, but, at a deeper level, might be related to 'karma' or some 'defect' at the soul level."
"They believe that Muzan's birth and mutation defiled the entire family's bloodline imprint at the soul level."
"Therefore, many of their secret researches over hundreds of years have focused on how to purify, strengthen, or protect the soul, hoping to resist, and ultimately end, this curse."
"However…" Kuroba gently shook its head, "This difficult research has, to this day, failed to truly change the fate of early male deaths in the Ubuyashiki Clan."
"Yet, these long and winding explorations, focused on the soul level, coincidentally… gave birth to a unique species."
It raised its head and looked at Cheng Mo: "That is—the Kasugai Crow, and we, the Silent Shadow Crows, are further cultivated and optimized variants based on this research."
Cheng Mo's gaze instantly sharpened, looking at Kuroba on his shoulder.