Reincarnated in Jujutsu Kaisen as Hashirama Senju

Standing on the tree, Gojo noticed how Hashirama was watching him intently.

With a smile, the man awaited the next move of his future student. He knew that Hashirama possessed that innate wood technique that allowed him to suppress cursed energy. If properly trained, it was very possible he could become one of the most powerful, if not the most powerful.

Satoru couldn't help but internally rejoice at the thought of someone surpassing him. He wanted someone to surpass him, craved that wonderful feeling of competition, and wanted to push his limits and become stronger and stronger.

Satoru's gaze, beneath his bandages, grew more intense as he saw Hashirama unconsciously using cursed energy and focusing it in his hands, raising his palms upward, just like Gaara did in the Fourth Ninja War. Only instead of sand, pillars of earth rose, trying to crush him.

With a smile, Gojo let his infinity take care of things. The pillars, with no visible effect on Gojo, struck the invisible barrier that protected him.

"So he can also manipulate the earth, huh?" thought Gojo.

He didn't expect this. Apparently, Hashirama's innate technique covered more than it initially seemed. Satoru Gojo was getting more excited, wanting to know how much more Hashirama's technique could do.

Hashirama's brow furrowed, so much so that it seemed he wanted to destroy everything. He didn't know how he was doing all this.

He was able to apply the five basic natures of chakra to his cursed energy. Not only that, but he could also create attacks with them by properly controlling the energy. Another thing he discovered is that he could suppress cursed energy using his wood element, in addition to his ability to innately use his abilities.

All of this entered his brain automatically after that last blow with black lightning that struck the invisible barrier protecting the bandaged idiot before he fell unconscious.

Tobirama, who was behind him, was just watching the battle unfolding before him. Although he had already discovered a small part of Gojo's ritual, he didn't fully understand why he was simply defending and not proceeding to attack. He decided to keep observing, his insight becoming sharper the more he questioned this power in general.

With a smile, Gojo began to speak. "Let's start with the basics, which is cursed energy," he said, resuming the words he had said before and had not been able to finish.

Calmly, while Hashirama planned another way to surpass Gojo's infinity, the aforementioned continued speaking.

"First, let's start with the basics." With a smile, Gojo Satoru raised a finger and calmly generated a small flame of cursed energy. "What you see here is cursed energy. It's what sorcerers use for everything related to Jujutsu sorcery, from using techniques to delivering blows and setting up barriers. Cursed energy arises from negative emotions that naturally flow through the body. Almost all humans emit cursed energy in some form, but not everyone can use it. Only a few can, and they should consider themselves fortunate as they are a special case." With a smile, Gojo waited for the information to sink in with his students. Hashirama, who initially seemed angry and ready to kill him, now appeared to be paying attention to his words.

Once everyone processed what he had said, Gojo continued speaking, "There are various theories about the specific location in the body where cursed energy originates. I firmly believe that cursed energy comes from the mind or the heart. However, my comrades disagree with the idea, and it is more commonly theorized that since negative emotions come from the stomach, cursed energy also comes from there," Satoru expressed with a smile.

"What you faced is called a curse. Generally, civilians who cannot control the flow of the cursed energy in their bodies continuously release cursed energy, which creates curses. Sorcerers control the flow of their cursed energy and accumulate this energy, allowing them to use it at will and also greatly reduce the leakage of cursed energy from their bodies. This also involves controlling their emotions. For example, if a sorcerer lets their anger flow, they will use up their cursed energy very quickly," Gojo concluded calmly, his smile never leaving his face.

Tobirama's gaze had become sharper in these moments. While Itama and Tsunade continued to process Gojo's words, Tobirama wanted to know more about this cursed energy. A hunger for knowledge arose within him. If cursed energy allowed one to do everything that both Gojo and Hashirama did, it meant that it should have a much broader range of uses than what he had been able to observe.

"What is cursed energy used for?" Tobirama asked, his mind eager to absorb as much as possible about the world he had stepped into.

Gojo's smile widened, almost wanting to split his face at noticing the subtle curiosity in his other white-haired companion.

"Well, raw cursed energy can be manipulated to harden or strengthen a sorcerer's body. Also, cursed energy can be generated as brute force to destroy a target. It can be hurled at the target or used to enhance a person's physical attack. Sorcerers of average or higher skill can see traces of cursed energy in addition to seeing curses. Similarly, sorcerers can conceal that trace to prevent being followed or tracked. Sorcerers can also perceive the flow of cursed energy in another person's body," Gojo said.

"There are sorcerers who can imbue their cursed energy with special properties, releasing it in the form of ranged attacks." Calmly, Gojo vanished from the tree where he was positioned and appeared in front of Hashirama, surprising him slightly. "Now, let's talk about cursed techniques."

"The primary formation of the technique will depend on its type and the abilities of its user. Additionally, the ability to manipulate cursed energy is required."

With the finger of his left hand still raised, Gojo began his explanation.

"Techniques are often quite diverse and tend to be exclusive to the user or their family or clan. The existing techniques are..."

"Innate Techniques (生得術式 Shōtoku Jutsushiki). These are techniques that form if the user is born with the ability to use them, meaning they are born with the innate talent to utilize a technique. These are exclusive to the user."

"An example of this is his brother Hashirama here," he said, and his right arm passed over Hashirama's shoulders and pulled him closer as if he were a celebrity, while his left hand pointed at Hashirama, who looked uncomfortable.

"His technique appears to be wood manipulation, but he is also capable of manipulating earth. Using natural logic, for a tree to grow it needs earth, and I wouldn't be surprised if he can also manipulate water. For that reason, he can manipulate his technique effortlessly, as people with these types of techniques naturally know how to use them, as if it were an extension of themselves." With a smile, Gojo observed how Hashirama's siblings looked at him in amazement, but he decided to continue.

"These Innate techniques are subdivided into:"

"Extension Techniques (拡張術式 Kakuchō Jutsushiki). Also known as Derived Techniques, these are techniques derived from the user's innate technique."

"Hashirama here with his earth manipulation derived from the wood manipulation technique," Gojo emphasized calmly.

"Maximum Techniques (極ノ番術式 Gokunoban Jutsushiki). These are more powerful derived techniques that an innate technique can achieve beyond Territorial Expansion."

"Hereditary Techniques (相伝術式 Sōden Jutsushiki). These are techniques passed down from generation to generation among clans of various shaman families. They are usually inherited by a person."

"An example of this is myself. My Unlimited Cursed Technique (無下限 Mukagen) is a hereditary cursed technique among the Gojo Clan members, with offensive/defensive attacks. It allows precise manipulation of energy at the atomic level, resulting in multiple techniques within the overall capacity."

"Only those who are part of the Gojo Clan are capable of being born with this type of ability. And those who possess the Six Eyes will be able to fully master the technique, etc."

Tobirama's eyebrows raised slightly at Gojo's technique, and then he murmured to himself, "Manipulation of energy at the atomic level."

Upon his explanation, Gojo decided to continue speaking without delay, continuing his lesson.

"Barrier Techniques (結界術式 Kekkai Jutsushiki). These are techniques that can be learned if the user has a certain level of cursed energy. It requires learning the usage formula from scratch to be able to recite the incantation and allow energy to flow through the user's body to activate the barrier. They are also commonly used among sorcerers."

Tobirama showed slight interest in this last technique, raising his hand to him.

In response to his inquiry about him, Gojo looked at him and allowed him to speak.

"How long does it take to learn it and what other requirements do you need to fulfill for this barrier technique?" Tobirama asked.

Gojo simply smiled again and responded plainly, "Barrier techniques can typically be used by any sorcerer with sufficient training, and usually you only need 1 to 2 years to learn them. I, for example, could help you with that if you wish."

Nodding slightly, Tobirama, although not entirely satisfied with the explanation, decided to delve deeper into the topic later.

"Reverse Cursed Technique (反転術式 Hanten Jutsushiki). These are techniques that require the use of positive energy. It requires complex control of cursed energy and very few sorcerers can use it. It is used for healing wounds or regenerating limbs. It is considered a cursed technique, but not a typical technique, and can only be used on oneself."

Tsunade's ears perked up at that. For her, everything else, while incredible, did not spark specific interest. From a young age, she had been drawn to medicine; However, due to her clan's restrictions on her, she was destined to be a breeding machine. Because of that, her attitude had become rebellious. However, now that the old man is dead, she can develop this field without any problem.

"There is only one person currently who is capable of using it on others. Even I, who am the strongest, have trouble using it on others, not to mention I can't do it," Satoru said with a smile.

Upon hearing these words, Tsunade's mind sparked and reacted. The desire to learn gathered in her mind. The option of wanting to learn from this person became strong, but to learn, she first needed to ask for the name of who could potentially become her teacher...

Tsunade raised her hand, her determined gaze fixed on the relaxed figure of Satoru, to which he smiled.

"Well, well, if it isn't the fearless Tsuna-chan," said Gojo Satoru.

"What's the name of the person who can use that reverse technique? Can he or she show me how to do it? I'm interested in that right now," Tsunade asked.

"Her name is Shoko. She's not a very good teacher, not as amazing as me, but she's my friend and I'm sure she'd be willing to give you a few lessons if you show talent for the Reverse Technique," replied Gojo.

In his mind, Gojo had already noticed the interest of both Tobirama and Tsunade in the world of Jujutsu. His gaze shifted to the timid young Itama, whom he had also noticed, though somewhat hesitant in the world of Jujutsu. Finally, Gojo Satoru observed the one who intrigued him the most: Hashirama. This boy had an innate technique, albeit somewhat simple from what he knew, yet it was interesting and powerful because he could suppress cursed energy at will.

He had thought about talking about domain expansion and seals but those were things that were still too complex for people who were just starting out in the world of sorcery.

"Well, let's call it a day for our lesson today. Come on, I'll show you who will be your comrades during your time at Jujutsu High School." With a joyful smile, he grabbed Hashirama and dragged him along while he protested with annoyance and resentment.