HxH: I Will Be Supreme

After he finished eating and got dressed, Oboro gave Gon some money and asked him to return it to Aunt Mito as a thank you. After all, he couldn't accept her hospitality without showing some gratitude. 

Gon took the money without hesitation.

When he returned home, Gon eagerly recounted the miraculous scenes he had witnessed in the forest. As Mito listened, Gon's image flashed through her mind unbidden. She began to suspect that there was more to Oboro than met the eye, though she kept her thoughts to herself.

In the days that followed, Gon went into the forest every day at dawn, bringing food to Oboro and shadowing him like an apprentice. He discovered many remarkable things about his new mentor. Oboro seemed to be able to communicate with the creatures of the forest, directing them with subtle gestures. Within a few days, he had mapped the entire ecosystem of the forest more thoroughly than Gon had in all his years there.

Oboro could effortlessly locate the habitat or nest of any creature, teaching Gon about nature's intricate food chain and survival dynamics through casual conversation. Gon also noticed that Oboro trained regularly, practicing martial arts in forest clearings or sitting in deep meditation, his aura barely contained.

During these training sessions, Gon would quietly observe from a distance, careful not to disturb his mentor's concentration.

The knowledge Oboro imparted was invaluable to Gon. Each day was filled with new discoveries, and he could hardly wait for sunrise to return to the forest. While Mito initially considered intervening, her grandmother's wisdom gave her pause.

In Ging's absence, Gon had grown up without a father figure. Oboro's presence, even if temporary, offered something Gon had been missing. More importantly, despite Gon's sunny disposition and popularity among the islanders, he had never found anyone who truly understood him.

As his family, both Mito and her grandmother sensed the same unique quality in Gon that set Ging apart from others. In Oboro, it seemed that Gon had finally found a kindred spirit. Eventually, Mito decided not to interfere with their growing bond, reasoning that Oboro would likely move on soon enough.

During his stay, Oboro continued his martial arts training with focused intensity. With his foundation, it usually took just over two months to master a new technique. This time, however, he didn't study conventional martial arts, but rather the traditional breathing and aura circulation methods that paralleled Nen training. Through systematic analysis, he realized that the breathing techniques from his previous life shared similarities with Ten and Ren - they increased blood flow, sharpened mental clarity, and strengthened one's life force. With dedicated practice, these methods could push the body beyond its natural limits and greatly enhance aura control.

Breathing techniques and martial arts followed different paths - one internal, one external. Yet mastering proper breathing proved to be just as challenging as learning martial techniques, if not more so. Oboro had to start with the basics: static breathing, abdominal breathing, rhythmic breathing, focused breathing, and finally the advanced breathing patterns used in internal martial arts. Only after mastering these basics could he move on to the more esoteric techniques of aura manipulation.

The martial arts techniques recommended by the system were rooted in efficient combat applications, not mere performance art. They were true killing techniques, similar in principle to the assassination arts of the Zoldyck family, differing only in their specific movements and training methods.

Two stones jutted from the surface of a stream - one large, one small. Oboro sat cross-legged on the larger stone, while Gon sat on the smaller one. Sunlight filtered through the canopy and warmed them both.

Although Oboro hadn't intended to teach Gon, the boy watched intently before he tried to mirror his meditation. To Oboro's surprise, Gon quickly realized that breathing was the key. Within moments, his breathing rhythm matched Oboro's, albeit at a gentler pace.

After a minute, Gon's face flushed red, his cheeks puffed out. Suddenly, he broke form, eyes flying open as he erupted into a violent cough, clutching his chest. As he started to fall towards the water, Oboro's hand shot out and caught him.

"I feel... my lungs are burning," Gon gasped, staring at Oboro's calm expression. "But my whole body... it feels warm and wonderful."

Oboro lifted Gon by his collar as easily as he would a kitten and jumped to the shore before setting him down.

"You're still growing, Gon. Your body - flesh, blood, bones and organs - they're all developing. You can't handle the full effects of this breathing technique yet." Oboro tapped Gon's chest lightly. "Especially your lungs. Different breathing patterns put different amounts of pressure on them. If you push too hard, you risk serious damage."

"That's incredible!" Instead of showing fear, Gon's eyes lit up with excitement. He clenched his fists and stared at Oboro with admiration. "Mr. Oboro, you can do this without any problems? You're amazing!"

Oboro ruffled Gon's spiky hair and stifled a yawn. "If you want to learn, start by slowing your breathing. Let your body adjust gradually before you increase the intensity and frequency."

"Got it!" Gon bowed deeply and nodded enthusiastically. "Thank you, Mr. Oboro!"

Seeing Gon's serious expression, Oboro felt a complex mixture of emotions. Getting to know Gon personally had shown him how difficult it was not to fall in love with the boy. His straightforward nature was disarming - as they said, sincerity was the ultimate weapon. Despite occasional nervousness, Gon showed remarkable emotional intelligence, easily reading the feelings of others and avoiding sensitive topics without being told.

This made their interactions surprisingly comfortable. Gon had correctly guessed that Oboro wouldn't mind him watching and learning. If Oboro had been disturbed by his presence, Gon would have noticed and kept his distance without being asked.

Besides, every action and word of Gon came from a place of genuine interest and respect. Looking at him, Oboro couldn't help but admire his pure nature. People like Gon were rare in every world.

If he was honest with himself, Oboro's first impression of Gon had been rather neutral. But now, things had changed. As long as they weren't forced into conflict, Oboro enjoyed their time together.

"This breathing technique will challenge your body at first," Oboro explained. "It alters your blood flow, increases organ efficiency, and stimulates growth. As you breathe, clear your mind and focus on feeling the air moving through your lungs. Gradually extend this awareness to your entire body."

"Understood!"

With that, Oboro slipped his hands into his pockets and led Gon out of the forest, the boy following closely behind, hanging on every word of instruction.