The forms of Nen's persistence can broadly be divided into three types.
The first is the constant aura, equivalent to life energy, continuously released from the human body as if it were a furnace.
The second is the aura unconsciously imbued into works by geniuses and masters in various fields.
This type of aura is like the materialization of craftsmanship, representing the pinnacle of their skills in their respective domains and their pure, undistracted will.
As a result, this Nen intent attached to works can often endure for a very, very long time.
The third is Post-Mortem Nen, lingering in the world like will-o'-the-wisps after death, carried by intense negative emotions.
The source of this aura is usually an unresolved obsession.
And because it is born from negative emotions, it possesses varying degrees of threat.
For Nen users, it's not too much of a problem, as long as they don't enter a state of Zetsu, they can generally resist the threats posed by Post-Mortem Nen.
But for ordinary people, encountering Post-Mortem Nen can result in severe consequences, ranging from loss of life to mental incapacitation.
This was Morrow's understanding of the three forms of Nen persistence.
So when he heard that the virus was connected to Post-Mortem Nen, he couldn't help but be surprised.
Or rather, he found it hard to imagine any correlation between the two.
In fact, since arriving in this world, he had seen plenty of Nen intent attached to antiques or handmade artworks, but Post-Mortem Nen, he had only encountered it once, on the airship.
"Related to Post-Mortem Nen... how?"
Morrow stepped over the scattered corpses and approached Sanbica, looking down at the well-preserved coffin.
Inside, he saw what appeared to be a stitched-together corpse, wreathed in smoke-like black energy that gave off an ominous impression.
Sanbica frowned deeply, staring at the black Nen inside the coffin, and explained in her characteristically soft voice: "The virus... was 'created' by this Post-Mortem Nen."
"Huh?"
Morrow blinked, studying the Post-Mortem Nen in surprise. "Sanbica, are you sure?"
"Yes."
Sanbica nodded lightly.
Morrow was stunned.
Post-Mortem Nen could do something like this?
"So... as long as this Post-Mortem Nen exists, it will keep producing the virus?"
He shifted his gaze from the Post-Mortem Nen in the coffin to Sanbica.
Sanbica sighed. "That's right."
Morrow inwardly muttered, This is ridiculous.
But then he thought of the few instances involving Post-Mortem Nen in the original story.
Even something like the Cat's Name, which relied on Post-Mortem Nen mechanics to instantly revive, existed; so a Post-Mortem Nen that endlessly generated viruses wasn't all that unbelievable.
It just went to show... Nen truly defied logic.
Not even death could constrain its bizarre and unpredictable nature.
Sanbica worriedly said, "With the 'OG' research data and my Nen, we should be able to develop an antiviral agent within a day. But since the source of the virus is tied to Post-Mortem Nen... if we don't purify it, it will keep reproducing."
Hearing this, Morrow's eyes flickered, and he fell silent.
Sanbica didn't notice his reaction, her gaze fixed on the Post-Mortem Nen in the coffin as she frowned and said, "My master is an Exorcist, but her ability can't target Post-Mortem Nen. Oh, right..." Suddenly, as if remembering something, the worry in her eyes faded considerably.
"I can ask my master if she knows any Exorcists skilled in purifying Post-Mortem Will!"
"Sanbica."
"Hmm?"
Sanbica turned to look at Morrow upon hearing her name.
Morrow reminded her, "The Post-Mortem Will isn't urgent. Treat the villagers first."
"Ah, right."
Sanbica nodded firmly, then bent down and reached through the swirling black Nen that resembled smoke, gently pressing her hand against the corpse in the coffin.
Seeing Sanbica's sudden action, Morrow was slightly startled.
He was about to stop her when he noticed the Post-Mortem Will in the coffin showed no signs of aggression.
The core lies in virus creation...
Morrow stared at the unresponsive Post-Mortem Will, lost in thought.
Even the most irrational Post-Mortem Will seems to operate by certain mechanisms.
As Morrow pondered, Sanbica withdrew her hand.
Her once jade-like, translucent palm, where veins were clearly visible, now appeared as though eroded by time, withered and wrinkled like tree bark.
This condition was likely due to the virus's effects, but strangely, the virus had taken hold unusually fast.
Morrow's eyes widened in surprise.
Holding up her aged right hand, Sanbica explained softly, "My Nen actively 'transfers' the virus into my body, forcing it into the symptomatic stage immediately..."
"Stop. I don't need to know this."
Morrow cut her off promptly.
Who would willingly reveal their Nen ability like that?
Sanbica understood this principle too.
She silently gazed at Morrow and said, "It's fine. My Nen only targets viruses... I can use my body to analyze the virus's weaknesses and derive a formula for an antidote."
"Your ability..."
Morrow glanced at her aged palm. "It's high-risk, isn't it?"
"Yes. If I can't analyze the virus within the 'time limit,' I'll die."
Sanbica spoke of death without a trace of emotion in her expression.
This wasn't about Nen, it was the resolve of a Virus Hunter.
Morrow felt a surge of respect and couldn't help saying, "Is it worth taking such a huge risk? With your expertise, you could just use Nen as a supplementary tool."
"I believe it's necessary. My master is an Exorcist, and when removing Nen, Exorcists inevitably take on the inherent risks of that Nen themselves... My ability was born under her influence, which always makes her sigh."
Staring at her aged hand, Sanbica murmured:
"But I know... fighting viruses is a race against time. So I'm glad to have this ability. Besides, analyzing viruses differs from Exorcism, the more I understand a virus, the lower the risk."
"..."
Morrow fell silent, filled with nothing but admiration.
This was the epitome of self-sacrifice for others.
Using her Nen ability and research data, Sanbica quickly developed an antiviral serum.
In just half a day, the villagers suffering from the virus gradually recovered, their lives no longer in danger.
—--
Meanwhile, Hisoka, utterly bored, had wandered off elsewhere.
—--
Inside the tomb research facility, Morrow turned his attention to the two figures in hazmat suits he had deliberately kept aside. "As agreed, I won't lay a hand on either of you before you leave this place, nor will I pursue you outside. So you're free to go now."
The two men exchanged a quick glance, looking as if they'd been granted amnesty, and frantically scrambled toward the passageway.
Morrow simply picked up his phone to confirm some details with Argo. After a few minutes passed, he released two coin-sized Shooting Stars from his other hand.
Whoosh... whoosh...
The Shooting Stars flew off his fingertips, curved through the winding tomb passages, ascended the stairs, and struck the two men with perfect accuracy, they had already reached the courtyard.
Thud.
Both men collapsed instantly.
Inside the tomb research facility.
Morrow set down his phone and approached the coffin.
Tree Rings...
Can it absorb Post-Mortem Nen?
He pondered.
—--
At the same time, Sanbica dialed her master's number.