Ryōsuke took his time reading the genjutsu scrolls and selected techniques that suited him. The first was Genjutsu: Shiranui, a Sharingan-based visual genjutsu that made the target feel as if their body were burning in flames.
The second was Genjutsu: Sharingan, a Sharingan-activated genjutsu superior to ordinary illusions, said to be capable of controlling a Tailed Beast.
The third was Demonic Illusion: Shackling Stakes Technique, a Sharingan-specific visual genjutsu.
Once the caster captured the target within the mental world constructed by the victim, the target would feel their body nailed down by giant iron stakes, unable to move, while suffering the illusion of pain. It was commonly used for interrogation.
This last technique was excellent. In the original story, Uchiha Itachi had used it to instantly defeat Orochimaru when the latter tried to seize his Sharingan. Ryōsuke wondered how his own ocular power compared to Itachi's.
His grandfather, who had been waiting patiently nearby, saw that his grandson had finished choosing and leaned in to look. He was a little surprised. The first genjutsu, Shiranui, was manageable. Most three-tomoe Sharingan users could learn it.
The second varied by the caster's ability, with the strongest even able to control a Tailed Beast. The third was difficult. Few in the Uchiha clan had mastered it.
Still, he trusted Ryōsuke. One glance at those crimson Sharingan told him enough. The redder they were, the stronger the ocular power.
"Grandfather, can Genjutsu: Sharingan really control a Tailed Beast?" Ryōsuke asked.
During the Nine-Tails' Rampage, Obito had controlled the Nine-Tails, even turning its eyes into Sharingan. If this technique truly could control a Tailed Beast, he needed to study it well.
"It might be possible," his grandfather replied, resigned. "But the required ocular power is immense. Three-tomoe Sharingan power is nowhere near enough. So during the Nine-Tails' Rampage, there's no way our clan was controlling the fox. To control the Nine-Tails would take tremendous ocular power."
Ryōsuke felt a spark of excitement. Indirectly, this confirmed that the Sharingan could control Tailed Beasts. If not with Sharingan alone, then with the Mangekyō Sharingan it should be possible. Especially for someone like Obito, whose powerful Mangekyō Sharingan and shattered psyche had driven him to slaughter even his own teacher and teacher's wife without hesitation. His ocular power was likely rare in Uchiha history. Ryōsuke decided he truly needed to learn this genjutsu.
Pointing to the three chosen scrolls, he asked, "Grandfather, you can use these three genjutsu, right?"
"Yes," the old man nodded. "All three. In my youth I was an Uchiha elite. Otherwise I wouldn't be the Great Elder."
"Let me read the details," Ryōsuke said, pleased. "Then please demonstrate. I'll copy them with my Sharingan."
His grandfather fell silent for a moment. Since Kakashi had gained a clan member's Sharingan and made a name for himself, the world assumed those eyes could copy any ninjutsu.
"The Sharingan has powerful insight," he said. "It can observe hand seals and chakra flow. Most ninjutsu can be copied. Genjutsu cannot. You might mimic the chakra flow, but the Uchiha's Sharingan genjutsu depends on ocular power and mental strength."
'No pressure,' Ryōsuke thought. His Sharingan was already three tomoe with strong ocular power, further boosted by the system. Crimson meant power. As for mental strength, his time with Kurenai had raised his chakra and, naturally, his mental focus as well. No need for tragedies like Obito's dead lover or Itachi's slain friend to spike his will.
"Grandfather, please demonstrate now," he said with a smile.
The old man had no choice. He activated his own three-tomoe Sharingan. Ryōsuke was unsurprised. A Great Elder of the Uchiha had to have three tomoe. His grandfather's eyes were a darker red, a sign he was past his peak.
He demonstrated the casting methods for all three genjutsu. The process was to refine chakra to the eyes, release genjutsu chakra from the ocular chakra points, transmit it through the opponent's five senses, then invade and control the opponent's neural system. The challenge was guiding chakra through the fine meridians to the eyeballs before firing the genjutsu chakra. The ocular meridians were tiny and fragile. Attempting this without fine control was dangerous.
Ryōsuke at least had experience driving chakra against the chakra limiter, so he already had some proficiency in channeling chakra through the pathways. He would be careful with ocular arts. His body's recovery was strong, but if the tiny eye meridians were damaged, who knew if they would heal? Better to be cautious.
"Ryōsuke, did you observe the casting methods with your Sharingan?" his grandfather asked.
"I've copied them," Ryōsuke said. "Now let me try."
He refined a trace of chakra and guided it through the fine meridians into both eyes. His eyes grew a brighter crimson. He started with Genjutsu: Shiranui, the simplest of the three. When the chakra reached the proper density, he moved to the final step, firing the genjutsu chakra. With no target available, he released it into empty space.
His grandfather's eyes widened. He could tell Ryōsuke had been cautious, using only a small amount of chakra, yet the genjutsu had undeniably been cast. The drawback was speed. But for a beginner, succeeding on the first attempt was remarkable.
Clearly, Ryōsuke had talent for genjutsu. With more training to raise his casting speed, he would soon handle Shiranui with ease. For greater power, he would need to feed more chakra into the eyes.
That depended on individual talent. Ryōsuke's three-tomoe Sharingan and high ocular power could sustain more chakra, so there was little to worry about. Another Sharingan genjutsu expert was about to emerge in the clan, and the old man felt satisfied.