In the end, Hiru still refused Sabito's "kind suggestion." After accompanying Sabito and Tomioka to help collect the bodies of the slain villagers, he returned to the Wisteria House.
On the way back, Hiru questioned Sabito in detail about demon-eaters. From Sabito, he learned that demon-eaters carried a small vial containing pills made from demon flesh and blood—capable of turning someone into a demon.
As long as one swallowed them, they would become a demon. In addition, he was apparently always carrying various medicines with wildly different effects, and was regarded as an outstanding pharmacist.
Regarding the former, Hiru felt it could be explained as part of a demon's disguise while living among humans—it sounded reasonably credible. As for the latter, Sabito's claim that he was an excellent pharmacist, Hiru remained highly skeptical.
Because on the very first day of his amnesia—if it could even be called amnesia—he had already rummaged through those medicine pouches and bottles. Not a single one smelled normal. Some of them felt dangerous just from a whiff.
Still, Sabito's words had struck a chord with him.
Humans had human ways of solving problems. Demons, naturally, had demon ways.
So after returning this time, Hiru began attempting to demonize himself.
The simplest way to trigger demonization was to subject the body to harmful external stimuli and force its defensive mechanisms to activate.
For demons, the most harmful things were, first, sunlight, and second, wisteria.
Sunlight was out of the question. Just looking at how he spent every day standing in the sun handing out blessings to the Kakushi made it obvious it had no effect on him whatsoever.
So Hiru asked the Kakushi to bring him wisteria flowers and wisteria poison at varying concentrations, and began his experiments.
When he ate the first wisteria flower, Hiru was genuinely nervous. But after discovering there was no reaction at all, he gradually increased the amount—moving from fresh wisteria blossoms, to medicinal powder ground from dried flowers, and finally to drinking cups of concentrated wisteria poison.
The more he experimented, the more Hiru began to question exactly what kind of being he was.
After consuming that much wisteria poison, forget demons—even a human should have felt their stomach burn like fire and vomited as a sign of basic respect for toxic substances.
So why was he just… burping?
Hiru found this impossible to understand, but at the same time, it emboldened him. Once his bloated stomach settled down, he took out the medicine pouches and bottles the Kakushi had delivered—items that originally belonged to him—and prepared to continue experimenting.
This second round of testing finally convinced Hiru that both Yoriichi and Sabito had been right.
He really was a demon unaffected by sunlight.
And he really was an outstanding pharmacist.
The former was proven by the fact that he kept vomiting blood after taking medicine and still didn't die.
The latter was proven by the fact that he truly managed to poison himself.
Among the many powders, liquids, and pills, three left the deepest impression on Hiru.
The first was a black powder with an intensely pungent smell. After ingesting it, his limbs went weak, and his internal organs were wracked with agony, as if countless sharp blades were cutting him apart from the inside.
The second was a colorless liquid with no smell at all. Drinking it caused no pain initially—until Hiru caught his own eyeball as it fell out, and, through that eye's vision, saw his skin rotting away.
The third was a pill that emitted an enticing fragrance and tasted pleasantly sweet. However, after swallowing it, Hiru completely lost consciousness. It was only when the Kakushi noticed he hadn't moved for two consecutive days and broke the door down that they managed to wake him from his stupor.
After regaining consciousness, Hiru first assured the panicked Kakushi that he was fine. Then, ignoring their attempts to stop him, he went right back to testing medicine and carefully recorded his reactions.
Finally, after being sent to the medical ward two more times, Hiru found the so-called demon-transformation pill.
It was a bottle of red bean paste sweets mixed with glutinous rice flour.
As for why this one—
After testing every single pill, Hiru concluded that this was the only one that produced no visible side effects after being eaten.
[So you carry this many poisons on you and aren't afraid of eating the wrong one? And with all this poison failing to kill me… what exactly did I do to myself?]
Hiru stared at the small vial containing the red bean sweets, his expression filled with deep resentment. He finally understood why he had ended up befriending so many strange people.
Because he himself was the strangest one of all.
Once the drug experiments were temporarily concluded, Hiru began taking demon-slaying missions again, hoping to induce demonization through the pressure of combat.
Yet the more he followed swordsmen to slay and capture demons, the more uncomfortable he felt.
First, the demons they encountered were far weaker than expected. Some of them didn't even require weapons—he could restrain them barehanded.
Second, whenever he faced demons that possessed Blood Demon Arts, Hiru always felt as though he had failed to do something critically important, leaving him inexplicably restless.
As these feelings continued to accumulate, on the fifteenth day after being affected, Hiru finally noticed new changes in himself.
On the wrist that had been grabbed by a demon, dark bluish-black claw marks appeared. Along with them came a hunger so intense it could drive someone mad.
Even worse, all the swordsmen around him smelled delicious.
[Why do I feel hunger?]
Hiru frowned as he watched the Kakushi cleaning up the battlefield, clutching his stomach.
[Is the effect of the Blood Demon Art not limited to amnesia?]
Unable to endure the tormenting hunger, Hiru began a second round of drug testing to distract himself, and also wrote a letter to Yoriichi, explaining his current condition.
After receiving the letter, Yoriichi rushed back from Hokkaido, wearing a grave expression for the first time since Hiru had been affected.
From that point on, Hiru could feel power surging endlessly within his body, while the desire to eat people grew stronger by the day. On the sixth day after black handprints appeared, Hiru finally entered a state of complete demonization.
Yet contrary to his expectations of losing control, his appetite was instead suppressed.
At the same time, he could clearly sense an unfamiliar power within his body pushing back against him. The sensation was like a side stitch from overexertion—he knew it was there, but couldn't immediately find a way to relieve it.
While maintaining this demonized state, Hiru asked Yoriichi about his Blood Demon Art and began experimenting with it. To him, every action felt new and fascinating.
This situation lasted another three days.
At last, Hiru successfully activated his Blood Demon Art once.
When he saw the orange stone extracted from his own body, memories of his paint box came flooding back.
A curse nearly slipped from his mouth. Still clinging to a sliver of hope, he dug the box out again. After seeing what was inside, Hiru finally muttered a low curse.
[Damn it. That demon died far too easily.]