This forest was quite special. It was purposely used biannually to conduct exams for lower ranked ninja called genin. More so, it had oversized insects and spanned over six miles (ten kilometers). Just that amount of space was more than enough for Jonathan to stay hidden.
It was first featured in the first part of the series. Most people who watched it knew little about it. What most don't know, though, is that the Chūnin Exams have already been taken. Because the forest wasn't particularly guarded, nor was it hardly touched during the nine-tails assault, it was the perfect spot for Jonathan to be in for the next week.
Deep into the forest, Jonathan finally stopped his run.
He looked at his surroundings. It was clear. Closing his eyes, he focused. He could feel that same chakra when he first transplanted the sharingan into his eyes. Causing it to flow correctly, Jonathan opened his eyes slowly. There wasn't much light within the forest because of how tall and thick the trees were. When Jonathan looked at his hands, he couldn't just feel his sharingan active, he saw it. A red glowing light was refracting from his palms.
Jonathan knew all about the sharingan. It was a mainstream power most people on earth would be content with having. First and foremost, Jonathan tried to control the amount of chakra consistently being drained from him to keep his sharingan active. He wasn't a naturally born Uchiha who developed it. He took it for himself forcefully. Moreover, he didn't gain a newly developed one. It was a sharingan with three tomoe.
Because Jonathan had transferred Uchiha DNA into himself, by this world's laws, he was now considered an Uchiha. Better yet, he didn't just use any Uchiha's DNA, he used the same Uchiha DNA that the original sharingan belonged to. Jonathan was fortunate that Hazuki's blood was compatible with his own. Even if it wasn't, Jonathan was proficient in medical ninjutsu. He would have used chakra to force her DNA despite the side effects. All this, however, was pedantic to Jonathan.
To help adjust to his new vision, Jonathan practiced turning on and off his sharingan. He could feel the chakra consumption. Proficiency in activating and deactivating it became natural. As long as he circulated the chakra flow from his optical nerve correctly, Jonathan speculated he could keep it active regularly.
Not a moment later, Jonathan began running around in the forest with his sharingan active. He could see the minute details of his surroundings. It wasn't like things were sharper, it was like he had foresight. He could tell in what direction insects were likely headed. Their very minute movements were capable of being predicted.
When Jonathan stopped by a large centipede, he stared at it. The sharingan may grant impeccable insights to its user, but its second advantage was creating hypnotic inductions. Jonathan was well familiar with performing genjutsu (illusion techniques). He had even tried practicing hypnosis on earth despite his many failures.
Manipulating his own chakra flow, he directed it to the centipede's cranial nerves. As long as the anatomy of an arthropod was similar to the one's on earth, he was confident. When Jonathan felt a connection had been made, he quickly disrupted the centipedes' senses. All species can be affected by illusion techniques. As long as that species had a forebrain, they were not excluded.
In order to use sharingan genjutsu, one required eye contact. Because this centipede was large in size, its eyes were more than seeable. It had instinctively focused on Jonathan the moment he came near.
The centipede had little to no control over what it thought it was sensing around it. It shrieked in its body, believing itself to be attacked by another creature far greater than it. Jonathan kept his focus. Though the centipede wasn't facing any physical damage, its very own mind believed it to be.
As inhumane as it looked, Jonathan didn't care for the things of this world. He was stagnant about doing whatever it took to achieve his goals. Even if it meant torture. Jonathan could feel a slight decrease in his chakra as the centipede squirmed, begging for the torment to end. After only a half a minute, the centipede died.
Illusion techniques were just what one thought they were: mere illusions. They were mainly used to stun or knock an opponent unconscious during battle. Granted, if an illusion was strong enough and the brain thought the body had died, then the target itself could truly suffer from death. Using chakra to induce such a pain has only amplified the effects of illusions.
Jonathan couldn't help but smile as his eyes widened. This was the first and only time he had felt a sense of joy in this world. Seeing exactly how effective genjutsu was in person, Jonathan felt he had obtained this world's primacy technique. His control was natural, and he felt a sense of authority.
Genjutsu was like hypnosis on earth. The moment a target was influenced by its illusionary effects, those subtle moments of inactivity could determine the outcome of the battle. And it wasn't just genjutsu, it was the sharingan's genjutsu. Activating it was easy. It only requires eye contact. There was a reason why one of the main antagonists of the series (Madara Uchiha) desired to use the greatest illusionary technique. He intended to use it to create an illusion of the world. Why? Because there was little to no defense against an illusion.