Because of the nature of his positive and negative experience points, every ability or item he could exchange from the System was tied to medical treatment in some way.
This meant that many techniques he remembered from his previous life simply did not exist in the inventory, including the mass-destruction Ninjutsu and Kekkei Genkai of this world. Otherwise, he would have had far more options to work with.
He searched for a long time. The resources exchangeable with negative experience points all carried darkened attributes, and after the System's conversion, ability-type resources would still be limited by chakra capacity, just like Blood Manipulation.
Measured against that benchmark, the weaker options weren't even worth considering. The stronger ones were genuinely tempting to look at, but he simply couldn't afford them.
"There are plenty of area-of-effect techniques too, but after the System converts them, their upper limits end up relatively low. They would still need to be developed further down the line. Setting aside how difficult that process might be, it feels like a waste of time."
After going through the ability list, he switched over to the item interface. He had been so focused on abilities that he had barely glanced at the item options before.
Military Music Dream (Flute Teigu) -- From Akame ga Kill!
Effect: Capable of freely manipulating the target's emotions. Can be used on the battlefield to boost morale. Covers dozens of distinct emotional states, though targets will develop resistance upon repeated exposure.
Secret Technique: Demon Summoning (strengthens the user).
(Note: This item is designated as a specific anti-enemy resource. Upon exchange, the resources of that world will be locked, but can be recycled to unlock.)
"Hmm?"
Something stirred in Yuji's chest.
He had actually watched Akame ga Kill!, that uniquely soul-scarring "healing anime." There were dozens of Teigu and Shingu scattered throughout the story, and the one that had left the deepest impression on him was the ice Teigu, Demon's Extract, which could freeze everything in its path. Its power had been outright heaven-defying.
Unfortunately, that one was nowhere to be found in the inventory. And even if it were, the experience point cost would almost certainly be astronomical. It would have satisfied his need for large-scale destruction perfectly.
As for this flute, he had some recollection of it. Its power was decent, but it had always been overshadowed by the more prominent Teigu and never got much of a chance to shine.
It was more of a support tool than anything else. Presumably, because it dealt with hypnosis, mental states, and emotional manipulation, the System had classified it as medically adjacent and added it to the library.
Alongside Military Music Dream, Yuji also spotted another Teigu called Spectator. Compared to the flute, this one carried a considerably more unsettling profile.
It granted the user five distinct abilities: Insight, Farsight, X-ray Vision, Precognition, and Illusion.
Insight allowed the user to read an opponent's thoughts through their expressions alone. Farsight allowed one to observe distant objects clearly.
X-ray Vision allowed the user to perceive targets regardless of any obstacles between them. Precognition allowed the user to anticipate the opponent's next move by reading the subtle shifts in their musculature.
Illusion allowed the user to project hallucinations into the opponent's mind.
Reading through the description, it sounded less like a tool and more like a powerful Kekkei Genkai-type Dojutsu had been handed directly to the user. He found himself wondering how it would stack up against the Sharingan.
Its inclusion in the System's library was likely due to the X-ray Vision component. While browsing the positive experience point exchange list earlier, Yuji had come across several X-ray Vision abilities that, for a doctor, functioned similarly to medical imaging.
The price tag on Spectator, however, read simply as "???" The
System hadn't even bothered to display a number. It was clearly beyond his reach for now.
"Hmm... there are also items and tools for controlling corpses. That tracks, I suppose."
He scrolled through the interface a while longer and gradually came to realize that the System held item exchanges to a stricter standard than ability exchanges, with higher price points across the board. The cost-to-value ratio simply wasn't as favorable.
After browsing through everything, his gaze settled back on Military Music Dream.
For one thing, its price was relatively modest, and since the System allowed it to be recycled, he had no fear of being permanently stuck with a poor investment.
More importantly, even after the System's conversion process, the chakra demand placed on the user was not particularly high. A moderate, sustained chakra output was all it took to produce a large-scale area effect, and that was enormously appealing to someone in Yuji's position.
Unlike ability-type resources, this Teigu's effectiveness was not directly bottlenecked by raw chakra volume.
Beyond that, the role it could play on a large-scale battlefield would be unmistakable. It also had clear utility in one-on-one situations.
Yes, targets would eventually develop resistance with repeated exposure. But that didn't make its true value any less significant.
"A flute... it's somewhat reminiscent of Tayuya's techniques from the Sound Four, several generations down the line.
Though her Ninjutsu blends Genjutsu with Yin Release energy and is built primarily for solo combat, the battlefield potential of Military Music Dream is on an entirely different level, far beyond anything she could compare to.
It can't deliver the large-scale destruction I was hoping for, but large-scale interference with enemy forces is nothing to dismiss either. And the main thing is that it's ready to use the moment I buy it."
Yuji turned the thought over for a moment.
Sound Release did exist in this world, but it was not the same thing as the Sound Four's Ninjutsu. Their techniques were simply the product of precise chakra manipulation, aided by instruments and equipment.
True Sound Release was a Kekkei Genkai in its own right, one that had appeared in the Land of Snow arc of the original story.
"After the System converts it, it will probably become a special classified ninja tool rather than a conventional one." Yuji's eyes flickered with quiet consideration.
There were quite a few items of that nature in the ninja world. The blades of the future Seven Ninja Swordsmen of the Mist came to mind, though their effects naturally paled in comparison to a Teigu.
If anything, the closest equivalent would be the Six Paths Ninja Tools. And beyond ninja tools, there were also Divine Artifacts to consider.
Yuji didn't exchange for it immediately. He sat with the decision for a while, turning over certain concerns in his mind, concerns that touched on matters at the Village level.
After a short while, he made up his mind and bought it anyway.
[Would you like to exchange for this item?]
"Yes!"
[Assimilating item... Please wait...]
[Congratulations to the host on obtaining a special exclusive ninja tool.]
A few seconds after his confirmation, a pitch-black vertical flute materialized in his hand. Three thousand negative experience points were deducted in an instant, leaving him with less than one thousand remaining.
Yuji considered for another moment, then used what was left to extend his Blood Manipulation skill tree, purchasing a Cursed Womb effect.
Certain special techniques could only be used with a Cursed Womb body, and further down the line he planned to acquire additional Cursed Womb effects along with a complete set of Blood Manipulation techniques.
Buying them outright through the System would save him the time he would otherwise have to spend developing them himself, time he almost certainly would not have.
He had originally intended to be more conservative with his expenditure, but the battlefield's demands on individual combat ability were simply too high to ignore. There was no point pretending otherwise.
Once all the subsequent techniques could be directly elevated to Kekkei Genkai Ninjutsu, his Kekkei Genkai ability would be considered to have reached a state of Major Achievement.
After that, when he had breathing room, he could research further on his own terms.
Part of what had drawn him to the Teigu in the first place was the math of it. The leftover experience points could be used to strengthen his personal combat ability just enough to improve his survivability on the battlefield and give him more tools to handle whatever situation arose.
"I don't know if this was the right call... but it's done now."
Yuji exhaled softly, watching the positive and negative balances in his experience bar bottom out completely. Then, exhausted down to his bones, he closed his eyes and fell straight asleep.