Stay with me, guys!! Please, don't die!! The next chapters have a high info dump, so I recommend ingesting them with caution. Consult your doctor if you experience the following symptoms after reading the chapters: headache, irritation, nausea, sudden mood changes, and swelling in the groin/scrotum.

Now, seriously, if you have swollen groin/scrotum, go to the doctor.

***

Tsunade's question wasn't a surprise to Yujin. He noticed that Tsunade was calmer. Perhaps she realized that Mito was up to something, and so a glimmer of hope appeared in her heart.

Yujin respected Mito's decision and, therefore, didn't respond. His silence, however, spoke more than a thousand words, and Tsunade smiled.

"I'm glad... It's something good amidst all the bad things happening."

He remained silent and didn't look in her direction. Tsunade didn't question why no one told her about it and simply accepted the situation with a grateful heart.

The two continued in silence for a long time, just enjoying each other's company. Yujin managed, after a while, to calm the fire he was feeling, a task quite easy for a master of Harmony. He had control over many physiological functions of his body, and although it was more difficult than usual, he achieved it with a little effort.

***

Yujin was getting ready to meet Might Duy, putting on clean clothes. His mind, however, was elsewhere. He wondered what that reaction with Tsunade was all about.

He knew what an erection was and what it was for; it wasn't his first time. However, it was certainly the first time he felt something like that near a woman, and it was also the first time he felt it with such intensity.

For some reason, when he realized that Tsunade was naked next to him, less than three meters away, his body started to have this violent reaction, something he had never felt before.

He wasn't sure what it meant, as it was the first time he felt this way. Even now, when he thought about that moment, his body reacted the same way, and he needed a dose of effort to calm down.

Taking a deep breath, Yujin calmed his emotions and focused on what was going to happen.

He and Tsunade left the house; Shizune was still sleeping. The sun had not yet risen. After a few minutes of walking, they arrived at Yujin's destroyed house and found Might Duy lightly exercising, doing some squats and push-ups.

When he saw the two approaching, he showed his usual youthful smile and spoke loudly.

"Good morning, Yujin, Tsunade-sama!"

"Good morning, Duy-san."

"Good morning, Duy. I see you're excited for our training today."

When he heard that, Duy started doing squats even faster and shouted loudly.

"But of course, I am! It's been a long time since I felt this passion for learning something new. Since my academy days."

Tsunade laughed when she saw Duy like this, remembering the academy days. Tsunade is a year older than Duy, so they didn't study together, but she remembers when he was young. Basically the same as today, full of energy. In a way, he is quite different from the other ninjas she met before.

"It's good that you're excited, but before we get to the practical part, I think it's good to start with the theoretical part."

Duy nodded vigorously and listened attentively, pausing his training out of respect. Tsunade already knew what Yujin was about to talk, but still listened carefully.

"Qi is very similar to Chakra. It's an internal energy that can be controlled to strengthen oneself. If I had to say the biggest difference between the two, however, it would be that Qi lacks versatility. While it's possible to transform Chakra into other elements like fire, water, earth, and wind, Qi doesn't have that capability. It's basically an energy cultivated within us with the ability to strengthen our bodies. Martial Arts were then created to use this energy efficiently. Now, can you imagine what Martial Arts were created for?"

"To defeat enemies, right?"

Duy quickly answered, thinking the answer seemed obvious, but he could sense by the way Yujin spoke that it wasn't so straightforward. Tsunade stayed silent; she had never heard Yujin address this in their previous conversations.

"Actually, there are two answers to that question, and it's unknown which one is correct. It's like the question of which came first, the egg or the chicken."

Duy and Tsunade fell silent and contemplated the question. They had never thought about it. What came first? The egg or the chicken? Both seemed possible. Impatient, Duy asked.

"So what's the second answer?"

"The second answer is that Martial Arts were created for self-improvement."

Neither of them understood what he meant, so Yujin explained slowly and calmly.

"Another way to call Martial Arts where I come from is Cultivation. That's because, according to those who say so, you cultivate yourself; training your body, disciplining your mind, perfecting your technique, and refining Qi. For those who call Martial Arts cultivation, it's not about how strong a person is, but about their mastery over themselves. It's about self-improvement until you reach the pinnacle of your potential. It's about being better every day. Personally, I prefer this answer."

Duy was speechless when he heard this. For some reason, although the first answer seemed obvious initially, the second answer resonated much more deeply within him. He thought about the past, the difficulties he had in becoming a ninja despite lacking aptitude, and how, with pure effort and determination, he became what he is today.

The word cultivation reminded him of how happy he felt every day as he grew stronger, and it touched him deeply. He felt that, even without cultivating Qi until today, he had cultivated his entire life.

Seeing Duy suddenly start crying left Yujin speechless. Tsunade also seemed surprised by the second answer, and she also liked it more, but Duy's reaction was much more dramatic.

"Yujin!!! You need to teach me how to cultivate for real!!! I want to be better every day!!! Perfect myself!!! Reach the peak of my youth!!!"

The more he spoke, the louder Duy's voice became, and the more excited he felt. Yujin respected his passion.

Suddenly, from one of the nearby houses, a woman shouted.

"Stop screaming, you lunatic, let me sleep, I have to work tomorrow!!!"

Duy didn't hear the shouts, and feeling that he could continue disturbing people, Tsunade and Yujin dragged the crying man to the training facilities.

After a few minutes of crying and some incoherent words, he finally calmed down, and Yujin continued the lesson.

"I want to make it clear that there is no correct answer to the origin of Martial Arts. It's possible that when they were created, they were used for war/self-defense. Or it could be that when created, the creator just wanted to improve himself. Either way, deciding what it will be used for is important when you start training. You can even use them for both, fighting and self-improvement. You decide. Just never betray the reason why you train. Our minds work with stimuli, and to function well, you need to give the right stimuli. If you have a conviction and betray that conviction, your mind will be stimulated in the wrong way, and it can negatively affect you in various ways. Consider yourselves warned."

Both nodded, and they continued listening attentively.

"The reason I'm saying this is that Martial Arts are about discipline. Duy has plenty of it. Tsunade..."

He honestly didn't know. Since he met her, he had never seen her train her ninja arts, but he didn't know if it was due to a lack of discipline or if she was going through a tough time and couldn't concentrate. Feeling the doubt in Yujin's voice, Tsunade felt embarrassed and didn't respond.

In fact, she hasn't trained for many years. For years, she has focused more on her medical studies, after all. Does that mean she lacks discipline? No. After all, studying is also a form of training; brain training.

"It's something important to think about before starting Martial Arts. My master spent a whole day explaining this to me when I started training, and honestly, it was very boring. I was eight years old, so I didn't care; I just wanted to learn how to punch to destroy a tree like he did. You guys are adults, so I'll leave it at that. After all, you also had your ninja training, which I think needs plenty of resolve to go through."

Feeling them both agreeing with his words, Yujin began explaining about Qi.

"So let's start talking about Qi. As I mentioned, it's an internal energy similar to Chakra, although much less versatile, but it doesn't mean it's weak. Our body can create Qi from breathing. There is an external energy, also called natural Qi or natural energy. This energy is everywhere. Our body can, through breathing techniques, draw this energy into our body. The energy is then refined. One part goes back to nature, which is the impure part. Another part stays in our body and merges with our physical energy, creating Qi."

Yujin sat on the floor at the end of his words and gave a demonstration. He breathed in and out, in and out. Neither of them could feel this energy or notice any difference, however. When he opened his eyes and saw them confused, he explained.

"You can't feel it, as I thought. Continuing. When natural Qi and physical energy merge, it spreads throughout the body through the meridians, occupying as much space as possible. There are levels of mastery over Qi: Beginner, Adept, Expert, Peak, Master, and Grandmaster. When you reach the Grandmaster level, breathing techniques become complementary because your body opens all pores, and you can passively absorb natural Qi, although more slowly."

Tsunade also didn't know this. It means that Yujin is constantly absorbing natural Qi and increasing his Qi reserves, even without doing anything. Duy then asked since he didn't know.

"Yujin, what is your level of mastery over Qi?"

"I am the 43rd Grandmaster of Yin-Yang Harmony school."

Duy nodded. He could feel Yujin's strength, and if he wasn't a Grandmaster, he would be very surprised.