Here's a revised version of your story with improved grammar, structure, and flow while keeping the core details intact:
It's been five years since I was born, and for the past three years, I've been training under Guy. My karma seal has been steadily transforming me, enhancing my regeneration capabilities to rival those of Hashirama Senju. My chakra reserves are also increasing at a remarkable rate, already at the level of a super Kage like Hashirama. To further enhance my reserves, I developed a Yin Seal—similar to Tsunade's but far more advanced.
Unlike Tsunade, who has a single seal on her forehead, I possess four Yin Seals: one on each palm, one on my stomach, and one on my chest. These seals were formed when I was just a year old, and I've been storing chakra within them for four years. Not only do these seals hold my chakra, but they can also store nature energy, much like the seal developed by Orochimaru. However, my version is perfect, designed by me—or rather, my other self. These seals will serve a vital purpose in the future when I unlock and master the Eight Gates without harming my body.
Under Guy's guidance, I've dedicated myself to mastering body techniques. Though I didn't initially care much for his techniques, his passion is infectious, and I've learned a great deal from him. While training, I discovered that feeding my body nature energy greatly strengthened my bones and muscles. By the time I turned three, I already looked like a five-year-old due to the rapid physical growth spurred by my intense regimen.
To push myself further, I began using gravity release ninjutsu, a skill that builds on mastery of earth release. Inspired by the Third Tsuchikage, Onoki, I manipulated gravity to increase pressure on my organs, bones, and muscles, making them stronger. (A.N.: This interpretation stems from my understanding of Onoki's ability to manipulate weight, which I associate with gravity release—please bear with this concept.)
Despite the rigorous training, I've always made time for my friend Naruto. After turning three, he was moved from the orphanage to his own house by the Hokage's decision. Unfortunately, things became harder for him as rumors about him being the Jinchuriki of the Nine Tails spread. Danzo, the so-called "Darkness of Konoha," was responsible for this. The villagers treated Naruto like he was the Nine Tails itself, cursing him as a monster. It's absurd, considering Naruto is the son of the Fourth Hokage and should be celebrated as a savior of the village.
To make things worse, the Third Hokage did nothing to stop this mistreatment. But unlike the villagers, I treated Naruto as an equal—like a brother. I spent my free time with him, sharing meals and conversations. He was deeply grateful for this kindness, and I could see how much it meant to him.
Recently, a new training partner joined us—Lee. Guy found him two years earlier than in the original timeline. Now five years old, like me, Lee has been training alongside us. However, due to my intense regimen, I already look like an eight or nine-year-old and have surpassed everyone except Guy himself in taijutsu. As I continue to grow stronger, I've also been gradually increasing the gravity pressure I place on myself. My grasp of gravity release is far beyond Onoki's, as I can manipulate it not only to negate weight but also to exert tremendous pressure on my body.
As I completed my 500th lap around the training ground, Guy approached me with a serious expression.
"How's your training going, Saru?" he asked.
I dropped to the ground and began doing push-ups as I answered, "As you can see, it's going smoothly. No burden on my body."
Guy nodded, his usual enthusiastic demeanor replaced by rare solemnity. "Hmm, that's true. You're incredibly diligent and physically fit. I think it's time to start teaching you the forbidden technique you've been pestering me about."
I stopped mid-push-up, a grin spreading across my face. "That's what I've been telling you! I'm more than ready for this technique, and I can handle its pressure."
Guy stared at me, his eyes burning with conviction. "Alright, but you must understand the dangers involved."
After explaining the risks, Guy demonstrated the Eight Gates technique.
"First Gate: Gate of Opening—OPEN!" he shouted.
Chakra surged through his body, and his aura transformed. The mental limiters were removed, and his power was overwhelming. While the first gate doesn't place strain on the body, Guy emphasized its proper use to avoid long-term consequences.
Watching his demonstration, I couldn't help but feel exhilarated. Soon, I would unlock these gates myself—but on my terms. Guy wouldn't suspect a thing since I had waited for his guidance. Everything was falling into place.
A.N.: Sorry for the short chapters, guys!