Uesugi Shinji didn't care that Shirokumo Hayama had fixed him with a murderous glare. He might have looked like a young ninja not yet twenty, but in truth, he had seen more combat than anyone else on this battlefield!
No one would have guessed that he was a transmigrator, and that his soul had arrived in this world only three years ago.
Before transmigrating, Uesugi Shinji had been a core member of a multinational mercenary team. For years, they had carried out any job their employers could afford, including assassinations, terrorist attacks, and the theft of classified information.
On his last mission, he had been tasked with stealing a chip called the "Light Brain" from a heavily guarded national research institute and destroying the cutting-edge equipment used to manufacture it.
After countless hardships and the sacrifice of many subordinates, Uesugi Shinji had completed the mission. But while delivering the Light Brain, his employer had tried to double-cross him. In the end, he had fought to the death and taken the ruthless employer down with him.
What he never expected was that, after dying, his soul would transmigrate into the body of a Kirigakure Chunin in this world. He had completely absorbed and inherited the unlucky Chunin's memories.
After transmigrating, Uesugi Shinji was surprised to discover that the Light Brain had come with him. It was a technological product that had already been fully energy-converted, and it had fused directly with his soul.
After a short period of experimentation, Uesugi Shinji mastered how to use the Light Brain.
The Light Brain had many uses, but its greatest strength, as far as he was concerned, was its immense analytical and computational power. Fused with his soul, it was like a part of his brain that he had been born with. It could seamlessly draw on the knowledge, experience, and understanding already in his mind to help him analyze things.
When developing ninjutsu, the Light Brain could find the simplest hand-sign forms and the fastest sequences for forming them.
When researching Sealing Jutsu, it could design the optimal sealing formula.
When training in Taijutsu, it could continually scan and analyze its host's condition, then devise the most effective training methods.
It had even analyzed the secrets of Kekkei Genkai, helping Uesugi Shinji transform from an ordinary ninja into one with the Ice Release Kekkei Genkai!
Kekkei Genkai fell into two categories. The first consisted of abilities that combined chakra natures with special bloodlines, such as the Sharingan of the Uchiha Clan and the Shikotsumyaku of the Kaguya Clan.
These Kekkei Genkai relied primarily on special bloodlines. Even if the Light Brain could analyze them, it couldn't help its host master their power. The only way would be to obtain the genes of a Kekkei Genkai user through a transplant, as in the human experiments conducted by Danzo and Uchiha Madara.
The second type of Kekkei Genkai did not rely entirely on bloodlines. Instead, it was created by combining different kinds of chakra—for example, Ice Release, formed from Wind Release and Water Release; Dark Release, formed from Lightning Release and Earth Release; and Storm Release, formed from Lightning Release and Water Release.
Although this type of Kekkei Genkai could be created by combining different kinds of chakra, doing so was extremely difficult in practice. The proportions of the chakra and the method of combining it to perform ninjutsu both had to meet exacting requirements.
In theory, any ninja who mastered two or more chakra natures could use this kind of Kekkei Genkai ninjutsu. In practice, however, almost no ninja could manage it through their own efforts. Most ninjas with these Kekkei Genkai relied on genetic memories passed down through their bloodlines.
Uesugi Shinji had Wind and Water chakra natures. Through the Light Brain's analysis, he found a theoretical method for combining them to create the Ice Release Kekkei Genkai.
For an ordinary ninja, this theoretical method was practically impossible to put into practice. It required an extremely high level of chakra control, since the two chakra natures had to be brought into perfect proportion and balance.
But for Uesugi Shinji, with the Light Brain's help, this requirement was not too demanding.
The Light Brain could scan the state of the chakra Uesugi Shinji controlled in real time and help him balance multiple chakra natures. Combined with his own decent talent and diligent practice, he managed to turn theory into reality and develop Ice Release through his own efforts!
Ice Release chakra was highly effective for offense, defense, and restraining enemies. Mastering the Ice Release Kekkei Genkai had given Uesugi Shinji a qualitative leap in combat strength.
In the three years since transmigrating, Uesugi Shinji had quickly distinguished himself among the village's Chunin. He and his two equally capable teammates had all been promoted to Jonin. One of them was Kisame Hoshigaki, his current partner.
Their squad currently served in Kirigakure's Assassination Squad, directly under Suikazan Fuguki, one of the Seven Ninja Swordsmen.
The Assassination Squad was responsible for eliminating anyone the higher-ups in Kirigakure considered a threat to the village's security. Their target this time was the Kirigakure ninja captured by Shirokumo Hayama's squad.
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