Naruto: The God of Bloodlines

Guy was hesitating because the inner gates were a highly risky technique that could harm or even kill the user. Yasu had already told Guy that he also had a considerable amount of chakra and could use jutsus, unlike Guy. 

Guy had taught Rock Lee the inner gates because Lee couldn't use other jutsus and could only rely on taijutsu, just like him. But Yasu was different—he hadn't learned other jutsus yet only because he couldn't reveal that he was already strong enough to become a shinobi. 

*"I think I'll wait until Yasu improves further in taijutsu and has a more resilient body before deciding. Since he's not going to participate in the war, he doesn't urgently need that kind of strength,"* thought Guy.

What Guy didn't know was that Yasu was thinking the same thing. He absolutely wanted to learn the inner gates, but he knew his body wasn't strong enough yet. He might even be weaker than Rock Lee was when he nearly became disabled from overusing the inner gates. 

Yasu wasn't in a hurry because he knew that in the future, he would awaken the Sharingan, other Kekkei Genkai, and possibly even the Mangekyou Sharingan if he were lucky enough for his bloodline purity to assist him. At that time, only the sixth and seventh inner gates would make a significant difference in battle. 

But Yasu also knew that currently, not even Guy was capable of opening the seventh inner gate. Therefore, Yasu needed to strengthen himself multiple times over before it would make sense to risk using this technique. 

---

A few more weeks passed, and Guy received a mission that required him to return to the war. This meant he had to stop teaching Yasu for the time being. 

Guy was deeply impressed with what Yasu had learned in just two months of training. Yasu had gone from someone who didn't know how to fight to someone who only needed more practice and a few techniques to fight on par with Guy. 

Of course, this was Guy being modest. In truth, Yasu could already be considered one of the best taijutsu fighters in Konoha, second only to a few members of the Hyuga clan. 

Yasu was already capable of fighting several chunin from Konoha using only taijutsu and winning. If he continued to strengthen his body through training, he could even defeat the village's jonin with taijutsu alone. 

Before Guy returned to the war, the two had one last friendly spar. This time, Yasu could properly react to Guy's attacks and engage in a decent match, even though Guy wasn't using his full strength. 

From an outsider's perspective, it would appear as though two individuals were moving at incredible speed, clashing multiple times within mere seconds. No one would imagine that Guy was wearing 12,000 kg in weights and Yasu was using 2,400 kg while fighting. 

After a few minutes, the two stopped sparring. Once again, Yasu was covered in bruises from failing to defend against several of Guy's attacks, but he was thrilled to finally be able to fight at such a high level. 

*"You've surprised me a lot, Yasu. I didn't expect you to become this strong in just two months. If I didn't know you, I'd think you'd already learned taijutsu before and had just forgotten it,"* Guy said, both surprised and proud. 

*"You taught me very well, Guy. Thank you for your help. Now I'm confident that I won't die facing any chunin from the enemy villages,"* Yasu replied, grateful. 

*"No need to thank me. We're friends, after all. I'm sure that if our roles were reversed, you'd teach me just the same,"* Guy said with a smile. 

*"Be careful on the battlefield when you return to the war. If you encounter strong jonin who target your team, it'll be hard for you to save your comrades,"* Yasu cautioned. 

*"I'll be careful, but if such an enemy appears, I'll fight to the very end to help my teammates survive with me!"* Guy said without hesitation. 

Yasu simply nodded, knowing it was pointless to say anything further. Even though Guy wasn't as obsessed with completing missions as Kakashi was, he wasn't the type to abandon his teammates to save himself. 

Yasu could only hope that his arrival in this world didn't change anything and that Guy would continue to live until the end of the anime's timeline. This way, Yasu would be strong enough to protect Guy after a few more years. 

After that, Guy left for the war with his team, and Yasu returned to his solitary training. Even though he hadn't focused as much on physical strength due to his taijutsu training over the past two months, Yasu still managed to increase the purity of the Sharingan Kekkei Genkai to 23%. 

It wouldn't take much longer for Yasu to reach 30% and activate the Sharingan. When that happened, Yasu already had some plans in mind to learn jutsu while still keeping himself hidden from the village and from Danzo. 

In the following weeks, Yasu continued his training. He had already mastered walking on water, and his chakra control had become very refined. Even so, he continued practicing walking on water to deplete his chakra entirely, enhancing the effectiveness of his taijutsu training. 

While Yasu was focused on continuing his training, he heard that Minato, Obito, and Rin had returned to the village. Obito and Rin were good friends of Yasu, as they were different from the other students who avoided talking to him because he was the worst student in the ninja academy. 

Yasu liked Obito's current personality and knew he would become powerful in the future. It had been easy to befriend Obito by telling him how he made a great couple with Rin and how he was better than Kakashi. 

By becoming friends with Obito, Yasu also grew close to Rin, who was kind to everyone. He even managed to get a little closer to Kakashi, who hadn't talked much to him since his father's death.