Chapter 66: Dangerous Tonbo 

The Barrier Development Team recovered the special kunai surrounding its test area. Each weapon marked an anchor used to measure how Sealed Horizon distributed chakra across distance. 

"Enough for today," Tonbo said. "Go home, eat, and return next week." 

"Yes, Captain," Tetsugan replied. 

One month of work had changed how the three specialists regarded their new leader. All had received focused barrier training from childhood, yet Tonbo's command of the fundamentals now exceeded theirs in several areas. 

At first, his knowledge contained obvious gaps. He understood barrier theory deeply but lacked familiarity with maintenance protocols, standardized seals, and the practical limits of systems operated by rotating teams. Tonbo asked questions without pretending otherwise. 

The gaps closed with unsettling speed. Each session produced a refinement, and each refinement led to a more precise experiment the following week. The specialists supplied institutional experience; Tonbo absorbed it and returned with structures none of them had considered. 

Tetsugan's Byakugan made the progress measurable. He could watch chakra thin across a boundary, identify stress around anchors, and distinguish a flawed seal from an inadequate supply. The other specialists translated those observations into maintenance procedures that ordinary barrier shinobi could repeat without Tonbo present. 

Sealed Horizon impressed them most. Expanded successfully, the barrier could protect Konoha's interior from an enormous attacker. If defenders kept a threat such as the Nine-Tails beyond the boundary, civilians and infrastructure inside would no longer remain exposed to every missed blow. 

The technique would not defeat such an enemy. It could turn survival from chance into a system. 

Tonbo checked the time. Barrier work occupied only two days each week; most of his schedule belonged to leading the Analysis Team. He settled into a routine of reports, coordination, home, and daily training without allowing either office to consume his family life. 

Two weeks earlier, he had mastered Bringer-of-Darkness Technique. 

The completed technique differed slightly from his expectation. It did not select a single pair of eyes. The caster projected genjutsu chakra across an area, plunging every affected enemy into darkness at once. 

It also persisted. A target could disrupt his chakra and recover sight for an instant, only to fall under the field again while Tonbo continued supplying it. Permanent escape required excluding the caster's chakra completely, leaving the affected range, disrupting Tonbo himself, or killing him. 

That persistence explained the technique's restricted status. Cast among allies without preparation, it could blind an entire formation and make Tonbo the single point of failure. Used with communication and protected positioning, it could deny coordinated sight to many enemies while Konoha shinobi fought from rehearsed signals. 

Susanoo offered one possible defense because its chakra construct enclosed the user and could prevent the field from reaching the body. Most shinobi possessed no equivalent. 

Tonbo left the training ground thinking about a less dangerous problem. It was Ino's birthday, and he still needed a gift. 

A woven figure of himself seemed perfect. Ino already admired his flower illusions, and no ordinary toy could compete with a miniature version of her favorite senior. 

The brilliance of the choice required no outside confirmation. 

At the Academy, the announcement of Iruka's class produced immediate order. 

"Iruka-sensei is coming. Sit down." 

"I am going to complain. Teachers should not use ninjutsu on students." 

"I complained to my father. He said the technique was an excellent improvement." 

"Then becoming Hokage can be someone else's dream. Mine is to defeat Iruka-sensei and whoever taught him." 

"Mine too." 

The second-year students hurried to their seats and stopped talking. Even an arrogant Uchiha boy and a reserved Hyūga classmate wore the strained expressions of children who had received a lesson through Eightfold Flavor. 

Only the consistently diligent students had escaped. They had heard enough descriptions to ensure their behavior remained flawless. 

Eightfold Flavor had changed more than noise. Homework arrived on time, practice weapons returned to their racks, and students who once ignored instructions now watched Iruka's whistle. Fear was not the educational philosophy he hoped to build, but order gave him room to teach before replacing fear with habit. 

Iruka entered carrying his books and wearing a friendly smile. The silent rows pleased him. Ebisu-senpai had struggled to control the same class; Iruka achieved obedience within a week. 

Teaching suited his ambitions, temperament, and carefully acquired skills. 

An Uchiha student raised his hand. 

"Uchiha Tō," Iruka said, "do you have a question? Remember that the restroom is for the break between lessons." 

"I do not need the restroom. I wanted to ask about your teacher. Someone who trained an instructor as capable as you must be an extraordinary shinobi." 

Every child listened. 

For a week they had wanted the name behind the technique. Most of the disruptive students had experienced at least one flavor. The rest had seen enough to understand that curiosity was safer than misbehavior. 

Iruka approved of the wording. "Good question. Notice how he approached the information indirectly instead of asking for a name without context. That is a basic intelligence-gathering method." 

The Uchiha boy abandoned subtlety. "Tell us who he is. When I grow up, I will defeat him." 

"He is a jōnin. Are you certain?" 

"I will become a jōnin too, and I have the Sharingan. I will make him regret creating this technique." 

The Hyūga student nodded beside him. Their clans rarely agreed so easily, but shared suffering had produced a temporary alliance across the classroom. 

"His name is Tobitake Tonbo," Iruka said. "He leads the Analysis Team. If any of you become strong enough, strike him several extra times for me." 1

The answer confused them. They intended to defeat Iruka as well; why was their teacher joining the revenge against his own teacher? 

Seven-year-olds understood the value of withholding part of a plan. They kept that detail to themselves. 

"First I will learn his technique," Uchiha Tō declared, "then I will use it against him." 

Others developed quieter strategies. Some would investigate Tonbo's habits. A few planned to exploit their age, behave charmingly, approach without suspicion, and attack when he lowered his guard. 

The plan assumed Tonbo could not detect children approaching from across a district and would accept sudden affection without suspecting a trap. None of them possessed enough information to recognize the flaw. For the moment, imagining revenge restored some dignity. 

Iruka let their plotting continue for another moment. 

"Enough. Mathematics begins now. Pay attention, or you will not grow strong enough to challenge my teacher. You will also receive Eightfold Flavor. I am generous, so you may select the variation." 

Every face fell. The room became perfectly still. 

Their determination to defeat both teacher and teacher's teacher grew stronger than ever. 

Iruka opened the mathematics text and began the lesson beneath the most attentive silence he had ever received.