There are many forms of Genjutsu, but killing an opponent directly with one is generally difficult.
Genjutsu works by disrupting the normal flow of a target's chakra, causing abnormalities in their five senses and trapping them within an illusionary world.
At its core, Genjutsu is a mental attack.
That does not mean it cannot kill.
For example, within Tsukuyomi, Uchiha Itachi could manipulate time, space, matter, and the victim's senses. Kakashi Hatake once endured what felt like three days and three nights of continuous torture at Itachi's hands inside Tsukuyomi's illusion.
Many ninja would be unable to withstand such overwhelming psychological torment and would suffer a complete mental collapse.
However, what Hayashi had used was not Tsukuyomi.
His Genjutsu was undoubtedly powerful, but not powerful enough to make someone like Danzo Shimura collapse and die outright.
So what exactly had Danzo seen?
Hayashi was curious.
Unfortunately, Danzo had no intention of answering.
As Izanagi activated, his body vanished into thin air once again.
Hayashi was not surprised.
After obtaining the Sharingan, he had gained a fairly clear understanding of Danzo's fighting style.
To put it simply, Danzo treated Izanagi like an advanced Substitution Jutsu, repeatedly throwing away his life to create opportunities. If he succeeded, he gained an advantage. If he failed, he simply died and tried again.
The current Danzo Shimura was not afraid of death.
After all, he had multiple lives to spare.
Possessing two of the most powerful bloodline abilities in the shinobi world, yet fighting in such a manner, was honestly a waste. Danzo excelled at schemes and political maneuvering.
As for actual combat...
That was clearly not his strength.
Yet Danzo insisted on fighting. Otherwise, all those transplanted Sharingan and Wood Release cells would have been for nothing.
The only thing Hayashi wasn't certain of was how many Sharingan Danzo still possessed.
The arm modified by Hiruko could hold a maximum of seven eyes, but Hayashi didn't know the exact number installed.
Still, he had a feeling it was seven.
Seven was a strangely significant number.
"To think I would actually fall under your Genjutsu."
Danzo's figure reappeared in the distance.
Chakra erupted beneath his feet as he charged forward.
His gaze was complicated and difficult to read. Dying in that illusion had been deeply humiliating.
Yet that same Genjutsu had also made him realize a painful truth.
No matter what he did, the Second Hokage would never have chosen him as his successor.
Danzo rushed forward and stopped ten meters from Hayashi.
His hands rapidly formed seals.
Dark and intricate curse markings spread across the ground, climbing upward from beneath Hayashi's feet and locking him in place.
The distance between them quickly shrank to three meters.
Danzo slowed his pace.
Although he had just died moments ago, there was no anger on his face. Instead, he appeared calm and composed, as though victory was already within reach.
"I used to fall for Uchiha Kagami's Genjutsu every time," Danzo said coldly. "Now it's you. Father and son alike, neither of you ever stop causing trouble."
A kunai appeared in his hand.
"Since he's already dead, you can go join him."
Danzo thrust the blade straight toward Hayashi's heart.
Hayashi did not move.
A surge of chakra burst from his body.
A massive blue skeletal figure materialized around him.
Susanoo.
The kunai struck the ribcage and shattered instantly.
The skeletal giant extended an arm and casually seized Danzo.
The curse marks restraining Hayashi vanished.
Susanoo's fingers tightened.
Crunch!
Danzo let out a scream as his body was crushed into a bloody mass.
Moments later, the corpse disappeared.
Danzo reappeared elsewhere and immediately formed another series of hand seals.
"Summoning Jutsu: Baku!"
A cloud of smoke exploded outward.
The giant dream-eating creature known as Baku emerged.
Among Danzo's summons, it was one of the most useful in battle. The bizarre beast opened its enormous mouth and unleashed a tremendous suction force, drawing everything in front of it toward its maw.
Even the chakra composing Susanoo trembled under the pull.
"Fire Release: Great Fireball Technique!"
A massive fireball several meters wide shot forward.
The Baku swallowed it instantly.
A moment later, its entire body shuddered violently.
Then it vanished in a puff of smoke.
The summon had been dismissed immediately.
Danzo's expression twitched.
He had only just summoned it, and it was already gone.
The chakra expenditure felt painfully wasteful.
At that very moment, Hayashi threw a Flying Thunder God Kunai.
His sleeve shifted.
Then he disappeared.
Instantly, he appeared above Danzo.
Blue chakra gathered in his palm.
"Big Ball Rasengan!"
The enormous sphere of chakra slammed downward.
Danzo had no time to react.
The gigantic Rasengan smashed him into the ground.
Upon impact, his body exploded into a mangled mess once again.
A massive crater formed beneath him.
Another Sharingan closed forever.
That's three.
Hayashi silently kept count.
This time, Danzo reappeared among a group of Root shinobi.
This couldn't continue.
Without the Uchiha Clan Massacre, Danzo had never obtained large numbers of Sharingan. Every eye he possessed had been gathered through years of effort.
Losing one every few dozen seconds was far too costly.
But without Izanagi, he would already have died three times over.
For the first time, Danzo fully acknowledged the reality before him.
The gap in combat power was simply too large.
Izanagi alone could not bridge it.
"Since that's the case..."
Without hesitation, he turned and fled deeper into Root headquarters.
Danzo no longer dared to remain.
Excluding Shisui's eye, he had only four Sharingan left.
Four remaining lives.
At this rate, that would only buy him a few more minutes.
In the original timeline, Danzo had not attempted to flee from Uchiha Sasuke.
The reasons were simple.
First, he had been in the Land of Iron, far from Konoha. His subordinates were dead, and Obito was watching nearby. Escape had been impossible.
Second, Sasuke's displayed strength had convinced Danzo that he still had a chance to win.
The current situation was completely different.
Hayashi was treating him like a child.
There was no possibility of victory.
Continuing to throw away his lives served no purpose.
More importantly, he was inside Root headquarters, surrounded by subordinates who could buy him time.
At Danzo's command, the Root shinobi charged forward once more.
Even knowing it was effectively suicide.
Hundreds of kunai rained through the air.
Various ninjutsu followed behind them.
The blue giant appeared again.
Hayashi brought his hands together.
Susanoo drew its spiral sword.
The enormous blade descended with overwhelming force, scattering the incoming ninjutsu.
The rain of kunai struck Susanoo's body and fell harmlessly away.
Hayashi was beginning to lose patience.
He was ready to charge straight through everything.
Several Root shinobi responsible for maintaining the barrier immediately paled.
Their hands flew through seals as they desperately reinforced it.
"Susanoo: Super Strength!"
Susanoo raised its massive fist and smashed it into the orange barrier.
Boom!
The collision shook the entire area.
The barrier shattered.
Hayashi stepped out of the hall.
But Danzo was already gone.
At that moment, a small Katsuyu crawled out from beneath his collar.
Hayashi gently tapped the slug's head.
"Copy that. Come in, over. Danzo Shimura is heading toward your exit. Do you read? Please respond."
"Copy that," Katsuyu replied. "The barrier has already been established."
Near the back mountain of Konoha, Minato Namikaze immediately rose to his feet after receiving the message through Katsuyu.