Chapter 78: Stealth 

After several days of increasingly careful, quiet observation, Iruka admitted that something was wrong with his students. 

Their fear had vanished. They laughed and whispered before class, behaved only when watched, and showed discomfort whenever he used Eightfold Flavor. Yet the instant they turned away, their suffering disappeared. The technique once left them shaken far longer. 

At first, Iruka believed they had adapted. Then the change spread from the third year to the second and fourth. Only first-year students, many of whom had barely learned to refine chakra, still reacted normally. 

He tested his suspicion by varying the imposed sensation and duration. The children produced different grimaces on cue, but their chakra recovered at almost exactly the same speed every time. A genuine target should have shown disrupted flow for several breaths afterward. These students recovered before Iruka even turned his back. 

Someone had found a countermeasure and distributed it through the Academy. 

Iruka chose intelligence work over confrontation. Before the next lesson, he transformed into the eraser resting beneath the blackboard and waited. 

The bell rang. Students entered in lively groups, some alert and others still rubbing sleep from their eyes. 

"We have Iruka-sensei today," one said. "I can't wait to pretend the flavor hurts." 

"Your acting was terrible last time." 

"Why bother staying? His trick doesn't work. We could leave and play outside." 

From his position beneath the board, Iruka gathered the essential facts. Tonbo's technique had been defeated, and children had deceived him for days. 

"The board is still covered from yesterday," another student observed. "Ren, you're the only third-year who has never been punished. A model student should erase it." 

Ren accepted the task without complaint. He picked up the eraser and frowned at its unusual weight. 

Iruka wanted to shout a warning, but revealing himself would end the investigation. He endured as the diligent child scrubbed his transformed body against the board from corner to corner. 

He should have chosen the lectern. 

Ren returned the eraser to its place and sat down. Four small legs emerged beneath it as Iruka attempted to escape through the open door. 

Mizuki entered carrying a stack of books. 

Iruka instantly withdrew the legs. 

"Good morning," Mizuki said. 

"Good morning, Mizuki-sensei." 

"Open Information Synthesis to page twenty-seven. We will reconstruct a battle from the evidence left at its scene." 

Mizuki filled the board with observations, hypotheses, and corrections. Every few minutes, he reached down and used the eraser. Once, his hand paused around it. Then he continued with particular thoroughness. 

By the time Iruka reached the faculty office, both sides of his face were raw and red. 

"Why did you transform into an eraser?" Mizuki asked, laughing openly. 

The other instructors covered their smiles with varying success. 

"You knew," Iruka accused. "You knew the entire time." 

Mizuki spread his hands. "Why didn't you say anything? I nearly mistook you for an intruder." 

In truth, he had first suspected that the Hokage assigned someone to monitor him. Discovering Iruka instead had been an unexpected relief. 

"I noticed the students behaving strangely," Iruka explained. "I was gathering intelligence." 

"Did you learn anything?" 

"They have a defense against my genjutsu, and it has spread through every year except the first." 

Iruka described the evidence: the false reactions, the synchronized recovery, and the boast he overheard. Several teachers immediately began comparing recent changes in their own classes. Students who once feared Iruka's whistle had indeed become bolder throughout the week. What appeared to be a general improvement in confidence now had a specific cause. 

The office quieted. Konoha's instructors had naturally devised personal counters to an irritating technique over time, but most required experience their students did not possess. A method simple enough to circulate across the Academy was a different achievement. 

"Who created it?" one teacher asked. 

"I don't know yet. The spread began with the third-years, so the source is probably among them." 

Ebisu chuckled. "Then accept the lesson. Teaching should depend on guidance, not coercion." 

Iruka nodded. His students had answered his shortcut by adapting around it. The result was impressive, but it also proved that fear could never replace genuine instruction. 

"Whoever solved it deserves recognition," another teacher said. "Analyzing a working genjutsu at that age is exceptional." 

Agreement moved through the room. Iruka touched his bruised cheek and wondered how to identify the inventor without teaching the children never to reveal success. 

Nearly a meter beneath the Land of Rain, Iwao pushed a narrow tunnel through saturated earth. 

Tonbo advanced directly behind him with Super Wide-Range Perception extended to its limit. Togekei and Murakumo held specialized scrolls at the rear, sustaining a barrier around all four shinobi. 

Above them, fine rain fell without pause. Heavy clouds dimmed the land even at midday. Civilians in waterproof coats followed muddy roads between settlements, while Amegakure patrols crossed the countryside at irregular intervals. 

The country had escaped direct participation in the latest great war, sparing some of the destruction suffered elsewhere, but decades of conflict around its borders remained visible. Metal roofs and tall drainage structures dominated its settlements, shaped by weather that never allowed water to be an afterthought. 

"How close?" Iwao asked. He had become the squad's unwilling excavation specialist. 

"Almost beneath the outer village," Tonbo said. "Slow the pace." 

Their solution combined two imperfect defenses. Earth blocked the rainfall that likely carried the sensory technique, while Tonbo's experimental barrier softened and redistributed the chakra signatures within. It did not make them disappear. It attempted to make four shinobi resemble the undisturbed ground surrounding them. 

Developing the barrier at their border shelter consumed most of a day. Tonbo adapted principles from Sealed Horizon while Iwao tested how earth chakra moved through different layers of wet soil. Togekei and Murakumo learned to maintain opposing halves of the formation so Tonbo could keep his perception active. A single imbalance would make their concealment brighter rather than weaker. 

Tonbo did not know whether Nagato's perception had already marked their entrance. The absence of an attack proved nothing. 

"Togekei, Murakumo, keep the barrier stable," he ordered. "Assume we have been detected and prepare to scatter on my signal." 

Both tightened their grip on the scrolls. 

Tonbo's awareness moved through the earth and into the rain-soaked streets ahead. Amegakure shinobi traveled across rooftops and elevated walkways. Civilians clustered beneath awnings. Water flowed through pipes, gutters, and channels in every direction. 

The density of movement forced him to narrow his attention. Instead of reading every signature, he searched for reactions to the squad's passage: patrols changing direction, civilians stopping without cause, or concentrated chakra waiting near the route. So far, the village behaved as though nothing unusual moved beneath it. 

Any one of those moving signatures could conceal an enemy body. Nagato and Konan were not the village's only capable defenders, and concentrating solely on them would invite an ordinary patrol to discover the squad first. 

The tunnel crept forward. 

Tonbo sensed the first dense concentration of structures directly above them. 

They had reached Amegakure.