Ren's heart stirred the moment Hebiji mentioned the recommendation.
He had wanted an opportunity to approach Tsunade for a long time—not because of her status as one of the Legendary Sannin, but because of the extraordinary techniques she possessed.
As a princess of the Senju Clan, Tsunade was unquestionably the greatest medical-nin of the current era. She had also elevated chakra-enhanced strength into a terrifying fighting style and mastered secret techniques such as the Yin Seal and the Strength of a Hundred Technique.
To Ren, she was practically a living treasure vault.
If he could enter the Advanced Medical Class and receive even occasional instruction from her, he would gain access to knowledge that ordinary shinobi might never encounter in their entire lives. More importantly, he might be able to select one of her techniques as a strategy target.
The potential rewards were impossible to ignore.
"Thank you for thinking so highly of me, Senior Hebiji." Ren accepted the offer without pretending to be modest, but instead of ending the conversation, he glanced toward Rin.
She was still moving between the wounded, carefully recording their injuries and monitoring their conditions. Her white coat was stained with blood, and several loose strands of brown hair clung to her forehead, yet she remained completely focused.
"Rin has also worked very hard in the medical field," Ren continued. "Her theoretical foundation is solid, and she is more careful than I am when examining patients. Could your recommendation letter include her as well?"
Hebiji followed Ren's gaze and observed Rin for a moment.
He had already noticed her performance. Rin lacked Ren's abnormal healing ability, but she remained calm under pressure and had not made a single serious mistake since beginning work.
"As for Rin…"
Hebiji rubbed his chin thoughtfully. "She is diligent, composed, and has a firm grasp of the fundamentals. However, the standards of the Advanced Medical Class are extremely high, and only a limited number of places are available."
Ren did not interrupt him. He simply waited for the final decision.
"I can mention her performance and include a recommendation on her behalf," Hebiji eventually said. "I will also speak to Lady Biwako personally, but I cannot promise that Rin will be accepted."
"That's more than enough." Ren smiled and inclined his head. "Thank you, Senior Hebiji."
"You're the one who earned this opportunity," Hebiji replied. "As for whether either of you can keep it, that will depend on your own abilities."
Before Ren could respond, the entrance to the medical ward was suddenly torn open.
Several Konoha shinobi rushed through the doorway carrying three unconscious men. Their uniforms were ripped, their skin had turned an unnatural bluish-purple, and dark blood dripped from wounds that should have already begun clotting.
"Lord Hayabusa!" the shinobi at the front shouted. "The Seventh Patrol Squad was ambushed by Sunagakure! They used some kind of poison smoke!"
Every medical-nin in the ward turned toward them.
Hayabusa Akiyama strode over, his already exhausted expression becoming even darker. "Those damned Sand shinobi again. Their squads have been crossing the border more frequently every day."
He clenched his jaw as the wounded were lowered onto empty beds. "They aren't moving like ordinary scouts. It feels as though they're searching for something, but whenever one of our patrols discovers them, they immediately attack to kill."
"Clear the area and give me room," Hebiji ordered. He hurried to the first patient and placed two fingers against the man's neck.
The pulse was weak and irregular.
Dark green blood seeped from several shallow cuts on the shinobi's arms. Thin black markings spread beneath his skin like a web, creeping steadily upward toward his shoulders and throat.
Hebiji opened one of the man's eyelids. The pupil barely reacted to the light.
"Respiration is slowing, muscle response is deteriorating, and the blood is no longer clotting properly." Hebiji looked toward one of the medical assistants. "Bring every general antidote from my medical kit. Hurry!"
The assistant returned moments later carrying several small vials. Hebiji selected three formulas and carefully administered a different one to each victim, hoping that at least one would slow the toxin.
Nothing happened.
The first patient began convulsing.
Rin immediately held his shoulders while Ren stabilized his head. Bloody foam gathered at the corners of the man's mouth, and every muscle in his body tightened violently.
"His airway is closing!" Rin warned.
Ren formed the necessary hand seals and placed glowing palms near the man's throat. He used the Healing Technique to reduce the inflammation, but the toxin continued attacking the nerves controlling the patient's breathing.
The second wounded shinobi suddenly vomited dark blood. The third remained completely still, his breathing becoming so shallow that his chest barely moved.
Hebiji examined the three patients again, and the color slowly drained from his face.
"This isn't a normal battlefield poison. It's a compound toxin attacking both the nervous system and the blood."
He smelled the blood, checked its viscosity, and studied the spreading markings. "At least two poisons have been combined, possibly more. One prevents the blood from clotting, while another disrupts communication between the brain and muscles."
Hayabusa stepped closer. "Can you neutralize it?"
"Not with the antidotes we have here." Hebiji's answer was immediate and grim. "I've never seen this precise combination before. Experimenting without understanding its composition could kill them faster."
The implications were far worse than the lives of three patrol members.
If Sunagakure had created a new poison that Konoha could not counter, every poisoned blade, senbon, and cloud of smoke would become a lethal weapon. A single Sand squad could leave dozens of shinobi dying before Konoha's medical division understood what had happened.
Hebiji looked toward Minato. "These men must be sent to the village immediately. Lady Tsunade is the only person capable of analysing the toxin and producing an antidote quickly enough."
Minato's expression hardened. "How much time do they have?"
"The two in critical condition may not survive until tomorrow morning." Hebiji glanced at the black markings spreading across their throats. "If the poison reaches the respiratory centre of the brain, they'll stop breathing completely."
"Then we won't waste another second."
Minato knelt beside the two critical patients and placed one hand on each of their shoulders. Hebiji quickly secured their bandages while another medic prepared sealed samples of blood and contaminated cloth for Tsunade to examine.
"The third patient's condition is temporarily stable," Hebiji said. "I'll keep him here and use medical ninjutsu to slow the poison. Take the samples with you and tell Lady Tsunade exactly what I observed."
Minato accepted the sealed case before turning toward his students. "Kakashi, Ren, listen carefully. I'm taking these two back to Konoha using the Flying Thunder God Technique."
He looked at Obito and Rin as well. "The four of you will remain inside Wildfire Outpost until I return. Help Hebiji if he needs you, or train within the camp, but do not approach the outer wall or leave the defensive perimeter."
Obito wanted to object, but the severity in Minato's voice stopped him.
"Sunagakure has already ambushed one patrol," Minato continued. "There may be other enemy squads nearby. Until we understand what they're searching for, assume the entire border is dangerous."
"We understand," Kakashi answered. Ren nodded beside him, while Rin promised that they would remain inside the camp.
Minato looked at each of them one final time. "Once Lady Tsunade identifies the toxin and I receive definite instructions, I'll return immediately."
A series of black markings spread from Minato's hands across the patients' clothes. Space seemed to tighten around the three figures for an instant.
Minato and the two poisoned shinobi disappeared in a yellow flash.
The entire journey from Konoha to Wildfire Outpost had required several days. With the Flying Thunder God Technique, Minato could return to the village before nightfall.
Perhaps he would even have time to eat dinner with Kushina while waiting for Tsunade's initial analysis. Ren almost smiled at the thought, but the third poisoned patient's ragged breathing immediately pulled his attention back to the ward.
There was still work to do.
Ren and Rin resumed treating the wounded while Hebiji focused on suppressing the remaining patrol member's poison. Whenever the man's condition briefly stabilized, Hebiji removed another blood sample, compared its colour and consistency, and adjusted the flow of medical chakra.
Later in the afternoon, Hebiji called Ren into the operating area to assist with a severely wounded shinobi. The man had a broken rib lodged dangerously close to his lung, and even the slightest error could cause fatal internal bleeding.
Ren maintained the patient's breathing and monitored his chakra network while Hebiji repositioned the rib. It was the first time Ren had assisted in a genuine surgical procedure, and Hebiji watched him closely throughout the operation.
Ren's hands never trembled.
Kakashi remained near the edge of the ward, his arms crossed and his masked face expressionless. He looked like an experienced jōnin supervising the situation rather than a young genin who had been ordered to stay out of everyone's way.
Obito, on the other hand, carried bandages, transported water, cleaned equipment, and moved supply crates for nearly an hour. Eventually, he ran out of useful tasks and began wandering around the ward in search of anything else to do.
"Obito?" Rin called when she noticed him heading toward the exit. "Where are you going?"
"I'm going to train for a while," he answered. "If they won't let me heal anyone, I might as well become strong enough to stop people from getting injured in the first place."
There was unexpected sincerity in his words. Rin gave him a small smile and reminded him not to leave the camp.
Kakashi watched Obito disappear through the entrance. After several seconds, he pushed away from the wall and followed him outside.
Ren noticed but said nothing. Obito had a talent for finding trouble, and Kakashi apparently did not trust him to remain unsupervised.
By evening, the most urgent patients had been treated. The field hospital finally became quiet enough for Ren and Rin to sit down and drink some water.
Rin held the cup between both hands, still processing what Ren had told her. "Senior Hebiji is really going to recommend you for the Advanced Medical Class?"
"He is going to recommend both of us," Ren corrected.
Rin blinked. "Both of us?"
"I asked him to include you in the letter." Ren took another sip of water. "He said your admission may be more difficult because the class has limited places, but he'll speak on your behalf."
For several seconds, Rin could only stare at him.
"That's incredible!" She clasped her hands in front of her chest, her exhaustion momentarily forgotten. "Thank you, Ren. If you hadn't asked, Senior Hebiji probably wouldn't have considered recommending me."
"It was only a small favour," Ren said. "You're careful, patient, and better at memorising medical theory than most students. I merely made sure Hebiji noticed what was already there."
A faint blush appeared on Rin's cheeks. "Even so, thank you. If we're both accepted, I'll work hard enough that you won't regret recommending me."
Ren smiled. "Then make sure you don't fall behind."
The tent entrance opened before Rin could reply. Obito and Kakashi returned from training, both covered in dust.
Obito's hair was even messier than usual, and a new bruise had appeared on his cheek. Kakashi looked almost untouched, which made it obvious how their spar had ended.
"I'm starving!" Obito announced. "Ren, heal my stomach. I think it's about to collapse."
"The only cure for that is food," Ren replied. "Unfortunately, your condition may already be terminal."
Obito was about to complain when one of Hayabusa's subordinates arrived carrying several meal boxes. The four young shinobi gathered around a small table and ate with the desperate speed of people who had spent the entire day working or training.
That night, Ren practised Hatake Swordsmanship in the courtyard to help digest his meal. His blade cut through the cool night air in smooth, controlled arcs, each strike quieter and sharper than the last.
Even while training, however, his thoughts repeatedly returned to the poisoned patrol.
Sunagakure was searching for something inside the Land of Fire. They had deployed a new compound poison, and their movements were becoming increasingly aggressive.
Those were not the actions of ordinary scouts.
Something was happening along the border.
Ren eventually returned to his assigned room and fell asleep with that thought lingering in his mind. The night passed without an alarm, an attack, or any obvious disturbance.
Yet sometime before dawn, one of the patients disappeared.
Early the following morning, Ren and the others rose with the first light.
Kakashi and Obito headed toward an open training area, while Ren and Rin accompanied Hebiji on his inspection of the medical ward. The patients were recovering well, and the anguished groans that had filled the tent the previous day had diminished to occasional complaints.
Hebiji examined each wound carefully while Rin recorded the results. Several of Ren's patients had healed with astonishing speed, and the residual energy of the Healing Brand remained stable.
When they reached a bed near the rear of the ward, Hebiji stopped.
The blanket had been folded back, and the mattress was empty.
"Hm?" He checked the wooden marker attached to the foot of the bed. "There was a patient here last night. Fujiwara, if I remember correctly."
A nearby chūnin looked up from the bandage around his shoulder. "Maybe he recovered enough to walk around. He kept asking when he would be allowed to leave."
Hebiji frowned. "A wounded shinobi should still report before leaving the ward."
"He probably went to stretch his legs," the chūnin suggested. "His injuries didn't seem too serious."
"Perhaps." Hebiji turned toward Rin. "Record his absence for now. We'll continue the inspection and ask the guards about him afterward."
Rin nodded and wrote down the missing patient's name.
The others soon moved on, but Ren looked back at the empty bed.
The sheet was neatly folded. There were no bloodstains on the floor, no discarded bandages, and no personal belongings left beside the bed.
It did not look like an injured man had wandered outside for fresh air.
It looked as though someone had deliberately removed every trace of his presence.
Ren's eyes narrowed.
Spies were hardly rare in the shinobi world, especially in a contested border region so close to the Land of Wind. Sunagakure possessed infiltration specialists, transformation experts, and even techniques capable of sealing or manipulating memories.
Sasori's Memory-Concealing Manipulative Sand Technique was particularly dangerous. A spy affected by it could live for years without knowing his true allegiance, only to have his memories restored when the proper trigger was activated.
Ren had no evidence that Fujiwara was an infiltrator. The man could genuinely have left the ward without permission.
Even so, the timing was suspicious.
A Sunagakure patrol had deployed a new poison yesterday. Minato had left the outpost to deliver samples to Tsunade. Now, before sunrise, one of the patients had vanished.
Ren decided to inform Hebiji and Hayabusa as soon as the inspection ended.
Elsewhere, in an isolated corner of the camp, Kakashi sat beneath a tree with his eyes closed. His short sword rested across his knees as he regulated his breathing and reviewed the movements of Hatake Swordsmanship in his mind.
Obito was supposed to be practising the Great Fireball Technique nearby.
Instead, he was lying on his stomach beside the wall, peering through a narrow gap between two supply buildings.
Kakashi opened one eye. "Obito, if you're finished pretending to train, move away from the wall."
Obito did not answer. His body had become strangely still.
"Obito," Kakashi repeated, irritation entering his voice. "What are you doing?"
"Shh!"
Obito raised one finger without looking back. The usual foolishness had disappeared from his expression, replaced by genuine suspicion.
"Kakashi, come here," he whispered. "Look at that man."
Kakashi rose reluctantly and approached the gap. Beyond it was a narrow path leading toward the outpost's restricted storage area, where medical supplies, mission records, and emergency communication scrolls were kept.
A lone Konoha shinobi stood beside the rear entrance.
His hospital robe had been concealed beneath a stolen patrol uniform, but strips of bloodstained bandages were still visible around his waist.
Kakashi's gaze sharpened.
The man checked both ends of the path before taking a thin metal tool from his sleeve and inserting it into the storage-room lock. His movements were controlled and practised—nothing like those of an injured chūnin taking a morning walk.
Obito leaned closer to Kakashi. "I saw him leave the medical ward before dawn. He was limping then."
They watched as the man straightened.
There was no pain in his movements now. No weakness, no hesitation, and not even the slightest limp.
Then the man's sleeve shifted, exposing the edge of a second forehead protector hidden beneath his uniform.
Its metal plate bore the symbol of an hourglass.
Sunagakure.
Kakashi's hand silently closed around the hilt of his short sword.
"That man isn't one of ours," he whispered.
At that exact moment, the disguised shinobi stopped picking the lock.
His head slowly turned toward the wall behind which Kakashi and Obito were hiding.
A cold voice drifted across the empty path.
"You two have been watching me for quite a while, haven't you?"