The Forward Operating Base in the Land of Rain was a miserable place.
It wasn't a fortress; it was a sprawling city of tents sinking into the mud. Over 1,500 Konoha shinobi were stationed here, a mix of Uchiha, Senju, Hyūga, and standard forces.
The air smelled of antiseptic, wet earth, and rot.
Inside the Command Tent, Fugaku Uchiha stood over a map. He looked stressed.
"The casualty reports are rising," a Medic Jōnin reported, wiping sweat from his brow. "Hanzō's salamander poison is bad enough, but now Sand Puppeteers have joined the fray. Their toxins are complex. We don't have enough medics to stabilize the frontline."
Fugaku tapped the table. He needed to deploy more forces, but he also had a political problem.
Ren Uchiha.
The boy had already humiliated Root and killed Cloud Elites. If Ren went to the frontline, he would rack up achievements faster than Fugaku could blink. The clan was already whispering about Ren's generosity with the Chidori. If Ren became a war hero, Fugaku's position as the unquestioned Heir would be shaky.
Fugaku's eyes narrowed. He saw an opportunity.
"Ren Uchiha has medical training," Fugaku stated.
The Medic Jōnin blinked. "He does?"
"Yes. His mother is a former Medical Chūnin, and he has mastered the basics. Given the crisis, we cannot waste such a resource."
Fugaku turned to the messenger.
"Summon Squad Satoshi."
Ten minutes later, Satoshi, Kaori, Ren, and Mikoto stood before Fugaku.
"I have new orders," Fugaku announced, his face unreadable. "The medical unit is overwhelmed. We are losing men faster than we can patch them up."
He pointed at Kaori and Ren.
"Kaori Uchiha. Ren Uchiha. You are temporarily reassigned to the Medical Corps. You will remain in the rear and treat the wounded until further notice."
Ren blinked. Rear guard?
"And the rest of the squad?" Satoshi asked, his hand tightening on his sword hilt.
"Camp Patrol," Fugaku ordered. "We need elite eyes watching the perimeter for saboteurs. You and Officer Mikoto will secure the camp."
Satoshi stiffened. Patrol duty was necessary, but it was glory-less work. It was the job given to Genin or old men. By keeping them in the camp, Fugaku was ensuring they wouldn't see a single second of combat.
"Understood," Satoshi said through gritted teeth. He couldn't disobey a direct order in wartime.
Fugaku looked at Ren, a hint of satisfaction in his eyes. Try becoming a hero while changing bandages.
"Dismissed."
The Medical Tent.
It was chaos.
Ren and Kaori walked into a scene from a nightmare. Shinobi were groaning on cots, their skin turned purple or green from various toxins. Medics were running back and forth with antidotes, looking exhausted.
"Get to work!" the Head Medic shouted at them, throwing a pile of bandages at Ren. "Station 4 needs chakra stabilization!"
Ren sighed, tying an apron over his combat gear.
"Well," Ren muttered to his mother as they walked to a patient. "Fugaku certainly knows how to sideline us. I wanted to fight Hanzō, not gingivitis."
"Quiet," Kaori scolded, though she looked annoyed too. "A mission is a mission. Heal this man."
Ren approached a shinobi whose chest had been slashed by a puppet. The wound was festering with a purple toxin.
Ren didn't need his Sharingan for this. He just needed his innate perfect control.
He placed his glowing green hands on the wound. He visualized the toxin molecules and pushed his chakra in to flush them out.
Flush. Knit. Seal.
The purple hue faded from the man's chest. The bleeding stopped.
"Move," a commanding voice cut through the tent noise.
Ren stepped back as a blonde woman stormed past him. It was Tsunade. She looked exhausted, dark circles under her eyes, her hands covered in blood up to her wrists.
She slammed her palms onto the patient Ren had just stabilized, checking his vitals.
"Stabilized?" Tsunade muttered, checking the chart. She glanced at Ren. "You did this? The neurotoxin flush?"
"Yes, Lady Tsunade," Ren said politely.
Tsunade narrowed her eyes. "Your chakra control is precise. Surprisingly so for an Uchiha. Usually, you lot just burn things."
"My mother is a medic," Ren gestured to Kaori, who was rapidly healing a burn victim nearby.
Tsunade grunted. "Good. We need every hand we can get. Don't waste chakra on small cuts. Triage only. If they can walk, kick them out."
She moved to the next bed, shouting orders. "Where is the Antidote for Puppeteer Poison Type-3? I need it now!"
Ren watched her go. The legendary Sannin was drowning in work. She was the best medic in the world, but she was only one person. She couldn't be everywhere.
"Mom," Ren whispered, moving to the next patient. "About my idea. The Healing Tag."
Kaori didn't stop working. "What about it?"
"Why hasn't anyone done it?" Ren asked. "We have Explosive Tags. We have Sealing Tags. Why don't we have a tag that just releases a burst of Yang Chakra to close wounds? It would solve this shortage instantly. Tsunade wouldn't have to run around like a headless chicken."
Kaori sighed, wiping sweat from her forehead.
"It's not that simple, Ren. Think about the nature of chakra."
She pointed to an Explosive Tag on a guard's pouch.
"Explosive Tags use Fire or lightning nature. Those energies are volatile. They want to expand. You just stuff them in the paper and put a weak lock on them. When the lock breaks, boom. Easy."
She then pointed to the green glow on Ren's hands.
"Yang Release—medical chakra—is different. It's life energy. It's fluid. It requires Intent."
"Intent?"
"To heal a wound, you have to tell the cells what to do," Kaori explained, knitting a wound on a patient's leg. "You have to guide the flesh. If you just seal raw Yang chakra into paper and release it... it won't heal. It will just disperse into the air as green mist. Or worse, it might cause tumors by stimulating cells randomly."
Ren paused.
That makes sense, he thought. Explosions are chaotic. Healing is orderly. Paper can't 'think'. It can't guide the chakra.
"So," Ren murmured, "the difficulty isn't storage. It's Programming."
"Exactly," Kaori nodded. "You would need a seal script so complex it acts like a brain. It would need to tell the chakra: 'Find damaged tissue. Stimulate mitosis. Stop when healed.' No Seal Master has ever figured out a formula that small and cheap."
Ren looked at the blank scrolls on the supply table.
To a normal ninja, writing a "brain" into a piece of paper was impossible.
But Ren had Omoikane.
His Right Eye wasn't for simple tasks like healing a cut. It was a super-computer. It could simulate millions of chakra pathways and write the algorithm needed to "program" the energy.
If I use the Quincy ability to manipulate Reishi... I can create a 'structure' for the chakra that holds its shape even after leaving the paper, Ren realized. And Omoikane can write the code.
He grinned. It was the smile of a man who was about to break the market.
"So," Ren whispered to himself, "I just need to write a smarter seal. Challenge accepted."
"Ren! Stop staring into space!" The Head Medic shouted. "We have a burn victim!"
"Coming!" Ren yelled back.
Fugaku thinks he buried me in here, Ren thought, walking toward the patient. But he just gave me the perfect laboratory