In the dim light of the cell, the prisoner's expression shifted with excitement when he recognized his visitor.
He hurried to the iron bars, gripped them with both hands, and asked in a hoarse voice, "Are you...?"
"It's been a while, Mr. Sid." Altaïr smiled. "I'm sorry I'm late. A few other quests held me up."
Of course, he knew exactly what Sid wanted to hear most.
"This is the gift I promised you." Altaïr handed him a photograph and a fang stained with dark, dried blood.
"The warden told me that prison rules won't allow you to keep them while you're serving your sentence. They'll hold on to both and return them when you're released."
Sid did not hear a word of it. Breathing hard, he took the fang and photograph.
The photograph captured the aftermath of the Hunt: the severed head of Diablon, the "Demon King."
Frantic roars, sobs, and laughter echoed through the prison for a long while.
Altaïr did not interrupt. He simply watched in silence until the man, seemingly driven half-mad, calmed down on his own.
Sid looked even more disheveled now, but his eyes were no longer clouded. All trace of despair had vanished from them, replaced by a brightness that was almost unsettling.
"Young man, I owe you a favor." His voice remained dry and hoarse, but his tone was utterly solemn.
"Hmm... Mr. Sid." Altaïr hesitated.
He had been wondering how to raise the subject at the right moment, and this seemed like the perfect opportunity. "If you don't mind, how about repaying that favor right now?"
"Right now?" Sid glanced down at the shackles around his wrists.
How am I supposed to repay a favor like this?
But he caught on quickly. "You want to learn something from me?"
"That's right. I heard you're from Shiki, Mr. Sid. Is that true?" Altaïr sat cross-legged in front of Sid's cell, clearly settling in for a long conversation. He even took some wine and food he had bought beforehand from the basket he carried.
The warden found this a little strange, but said nothing.
According to his superior, the young visitor was apparently a formidable Hunter, and the Guild had already put in a word on his behalf.
As long as the visitor did not break any rules or step too far out of line, the warden could look the other way.
With the cloud over him finally lifted, Sid revealed himself to be an easygoing man.
He swept his tangled hair back and tied it loosely, then settled to his knees across the iron bars from Altaïr.
"Ask whatever you like. My past, my experiences, anything at all. I'll answer without holding anything back."
Altaïr did not beat around the bush. He poured Sid a cup of rice wine from Shiki, handed it over, and asked directly, "Mr. Sid, have you ever heard of Devouring Demon?"
Sid paused as he accepted the cup. "Devouring Demon? When you asked me to repay the favor, did you mean you wanted its training method from me?
"May I ask where you heard that I knew this Hunter Art?
"The technique is quite obscure, and I rarely use it. There shouldn't be many people who even know about it."
A glimmer of delight flashed in Altaïr's eyes.
He had only been taking a chance. Sid was from Shiki and used a Long Sword, so Altaïr had hoped he might at least have heard of the Hunter Art and be able to offer a clue.
He had never expected Sid to know it himself!
"To be honest, I didn't know you could use it," Altaïr said, raising his cup in a toast. "I only learned from an elder that this technique circulates among Long Sword users in Shiki. That made me think of you, so I came specifically to ask about it."
"I see..."
After a moment's thought, Sid nodded. "Of course I can teach you how to train in the technique, but there are some things I need to explain first.
"It may not be some secret ultimate art, but it isn't a technique to be used lightly. Its cost is steep, and it is dangerous enough to kill the user. It is widely regarded as a forbidden technique.
"Before I tell you how to train in it, I need to make those risks clear."
"Please, go ahead." Altaïr took out his notebook, ready to write.
A subtle look crossed Sid's face. The habit of taking notes was quite rare among Hunters.
"First, I want you to understand Devouring Demon correctly. Few Hunters know the technique, and many of those who do misunderstand it."
Sid paused and looked up at Altaïr before continuing. "At its core, Devouring Demon forces the user's blood and vital energy into a violent boil, trading self-inflicted harm for greater strength over a short period.
"That violent overdrive inflicts tremendous damage on the user's body and can even burn someone to death within a minute. The soul-deep agony is more than an ordinary person can endure. Even a brief activation can severely damage both body and mind.
"Without its secondary effect, the technique would have no reason to exist.
"And that secondary effect is precisely what most people misunderstand about Devouring Demon."
Altaïr asked in surprise, "Doesn't it absorb a Monster's flesh, blood, and life force to heal wounds?"
"Just as I thought." Sid sighed. "Is that how your elder explained it?
"You're a High Rank Hunter. You should understand the body and Spirit well enough to answer this yourself. Could a human body possibly absorb a Monster's flesh, blood, or life force to heal its own wounds?"
"It... really doesn't seem possible."
Altaïr frowned as he thought back. Gordon had been the first person to mention Devouring Demon.
At the time, Gordon had mainly been discussing special equipment with similar effects and had brought up Devouring Demon in passing. He had not seemed particularly familiar with the technique itself, only saying that Ms. Hayata might know it.
As a Long Sword user, Ms. Hayata clearly understood it better, but she had said little. She had only explained that she could not perform it and warned Altaïr that it was dangerous and he should not learn it.
Had he simply filled in the blanks himself?
Altaïr shook his head. "I must have misunderstood what my elder meant. So... what exactly is this so-called 'healing effect'?"
"Think of it as a stimulant, something like an adrenaline rush. It makes you ignore both your injuries and the agony of your boiling blood, while driving your fighting spirit into an even fiercer eruption.
"Once it carries you through the crisis, you need to take a Potion immediately to treat the injuries. Otherwise, the danger is extreme.
"Simply put, Devouring Demon began as a battlefield killing technique meant for desperate, life-or-death struggles. Only later did some Hunters adapt it into a Hunter Art.
"Calling it a technique that hurts you more than your enemy would be an understatement. So, do you still want to learn it?"
"I see..." Altaïr could not hide his disappointment.
If that was how Devouring Demon worked, it would do nothing to solve the problem posed by his excessively powerful eruptions of Spirit energy.
But he quickly adjusted his expectations and nodded to Sid. "Yes, Mr. Sid. Although it's a little different from what I imagined, I still want to learn this technique."
There was no such thing as having too many trump cards. Even if he never used it directly, the method of controlling that violent overdrive was novel and might offer him valuable insight.
"You still want to learn it after hearing all that?" Sid shook his head with a wry smile. "No wonder you reached High Rank at such a young age and even managed to Hunt Diablon, the 'Demon King.' It seems you're a madman too."
"I'll take that as a compliment." Altaïr smiled and refilled Sid's cup.
Sid drained it in one gulp. "Since you've made up your mind, I won't try to dissuade you. Doing so would only insult your resolve.
"But remember this: it isn't a technique you can practice in the Training Area. Only a blood-soaked struggle to the death can make you embody Devouring Demon and withstand the searing pain and damage caused by that violent overdrive."
Sid paused, then repeated the same words Hayata had once said to Altaïr.
"Offer your life in sacrifice, and the demon blade will manifest. Wielder and blade become one, assuming the form of Devouring Demon.
"Without an offering to sate it, it will ultimately destroy its wielder."
P.S. In the game, the Devouring Demon can absorb blood, but if we consider it in a realistic sense... a person using explosive Spirit to drain blood just seems a bit inhuman, so I need to find a way to make it make sense.
Thus, other people's Tempered Spirit Blade is a "realistically nerfed version," but the protagonist can get a "full version."