Lightning Release plus Water Release. The fusion of these two chakra natures creates the Storm Release Kekkei Genkai, a power rumored to circulate in the Land of Lightning. It can make straightforward Lightning Release jutsu bend and twist like water, turning at impossible angles.
Hatake Sakumo was a genius, no doubt about it. But the white-haired boy was still just a kid, his chakra limited by his age. He much preferred practicing swordsmanship, and when it came to mastering chakra nature transformations, he was a bit out of his depth.
Fortunately, Emiya Shirou was a surprisingly good teacher. As a ninja proficient in all chakra natures, guiding someone to master Lightning and Water Release was relatively easy.
He could directly transmit chakra, allowing Sakumo to get a feel for the transformations step-by-step. This method was usually risky, it could easily lead to out-of-control chakra and injury, but for Shirou, such minor problems were child's play.
Sakumo's progress was rapid. Fusing a Kekkei Genkai wasn't so simple, but mastering two chakra natures in such a short time was already proof of his genius. This, of course, earned him more than a few unhappy glares from little Tsunade when she came back from the academy.
"I'm not happy," she pouted, watching Sakumo train. She was still stuck on the basics of Yang Release. "Why can't I be a genius like Senior Hatake!"
"The conditions for becoming a medical ninja are incredibly strict," Shirou said, noticing her mood. His tone was a bit sterner when he taught her. "But that doesn't mean those who can't become one can't still be excellent people. Tsunade, as the future's most outstanding medical ninja, your talent is already more than enough."
"Is it? Hahahaha!" she cackled, a laugh that was eerily similar to Hashirama's.
He's spoiling her way too much, Sakumo thought, feeling a little miffed at the blatant favoritism.
And he's a bit too dismissive of ordinary ninjas like us.
That night, an unusually large number of seriously injured were brought in. It wasn't until the first rays of morning sun hit the hospital corridor that Shirou was finally able to sit, seriously writing up his case scrolls.
"Good news from the front lines today," Sakumo said, his face flushed with excitement. "Lord Second Hokage led our ninjas to defeat the Sand Village's army and forced them to sign a peace treaty!"
The war was finally turning in Konoha's favor. Tobirama's victory had crushed the Sand ninjas with lightning speed, proving Konoha was still the strongest village in the world. Even without the First Hokage, they could still protect their home.
"If you're not too tired," Shirou said, seemingly uninterested in the news of war. He glanced at the filled scroll in his hand, then at Tsunade sleeping soundly on the bench. "Go get me a few more blank scrolls. Don't wake her up."
"Yes," Sakumo replied, vanishing with the Body Flicker Technique, his heart still soaring with excitement.
The whole village was buzzing with the victory report. But while the ordinary ninjas were fired up, Tobirama's will to fight was slowly weakening. As the Hokage, he had to consider much more than just the battle at hand. The First Great Ninja War had started at the beginning of his tenure, and the pressure was immense. Defeating the Sand Village was only a small relief.
After forcing the treaty, he led his Hokage Guard Platoon north, handling military affairs and reviewing the casualty reports.
"If it were possible," he sighed, looking at the data from Konoha Hospital, "I'd really send Lord Emiya to the front lines." He felt a pang of regret. If he had researched Edo Tensei back in the Warring States period and brought Shirou back then, the Senju clan's losses might have been drastically reduced.
The man was a monster. In his reanimated body, he needed no rest, treating the injured 24/7. He could complete a life-saving surgery in under half an hour. It pricked his conscience a bit, but Tobirama had long ago decided that to protect the village his brother built, any means were necessary. He could afford to abandon his already minuscule conscience.
"As expected of Lord Emiya, he's saved so many people from the rear," Hiruzen scratched his head. "But he probably won't be willing to come to the front lines. I heard he was in a foul mood when the war broke out. He's always disliked conflict."
"It's not necessarily impossible," Danzo immediately sang a different tune. He had earned a lot of merit in this war. With the cursed seal Shirou had given him, he had rampaged on the battlefield, finally standing on equal footing with Hiruzen.
"Lord Emiya has only seen the injured in the rear. If we let him see the battlefield strewn with corpses, let him see people he once saved now dead, let him see how tragic this war truly is... then, if we persuade him a little, he'll surely be willing to help. It will allow us to win this war faster!"
The cursed seal was powerful. It converted nature energy into chakra, allowing him to stand out in the war. But Hiruzen had gained even more from it, knowing better how to use it to amplify his ninjutsu. His terrifyingly powerful five-nature jutsu could suppress an entire area, crushing the older generation of Sand ninjas. His prestige grew, but so did the disputes between him and Danzo.
"Hiruzen! We can gain more!"
"Danzo, we've already gained enough." Hiruzen was trying to be the voice of reason.
Konoha had a stable victory, thanks in no small part to Shirou. There was no need to use extreme measures and ruin their relationship with him. "You know he doesn't like his power being used in war. We shouldn't force him."
"He won't mind that much!" Danzo snorted. "He's already saved hundreds. If the village's ninjas obtained his power, it would reduce our losses by over a hundred squads! If we act in the name of peace, we can surely persuade him. This is all for Konoha's victory!"
"This will desecrate his reputation," Hiruzen argued, but he knew Danzo's logic was tempting.
Why not take more extreme measures?
But these two were just guards; the only one who could truly decide was Tobirama.
"You two, look at this first," Tobirama said, his face so gloomy it looked like it was about to rain. He held up a battle report. "According to the sensory team, the Rock Village has assembled a force of at least four thousand on our northern border."
"How can there be so many?" Mitokado Homura's eyes widened. Konoha had less than a thousand on that border.
How could they fight?
"This is normal," Hiruzen said, drawing on what he'd learned during his travels. "The Land of Earth has many mountains and treacherous terrain. They rarely experienced war and have a large population. They can use at least five thousand ninjas for foreign wars, and I heard they have a special unit of Kekkei Genkai users."
The tent fell silent. The enemy was too strong. Unless the First Hokage was alive, winning would not be easy.
Danzo saw his opening. "For Konoha, we can let more people obtain Lord Emiya's power! Only in this way can we achieve victory!"
"That is one way," Hiruzen conceded, "but we ultimately need to get his recognition of our will for peace, not by using dark means."
He turned to Tobirama. "When Danzo and I were with Lord Emiya, the people of the Rock Village owed him a big favor. Can we ask him to use this favor to help us reach a peace treaty? It would avoid more sacrifices. Even if it fails, at least he will see that we have worked hard for peace. He, who loves peace so deeply, will recognize our attitude."