(Gohan P.O.V)
After making Goku and Yamcha go through their daily training today, I mentally prepared myself for what I was about to do. Goku was now 4 years old, the fact that he hit his head was a blessing in knowing his birthdate, May 9th. It was funny how he was born on the same date that fans chose to celebrate the character's birthday, due to a pun on the pronunciation of numbers in Japanese in my past life.
It was now June 12, 738, and I had just turned ninety. Despite my age, I still moved as if I were in my sixties, a true wonder, indeed.
Currently, I was watching the sun set, I knew that today would be a full moon night, I trained hard for this moment, I was ready to begin Goku's training to master his transformation into Oozaru, I would take my grandson to the Devil's Desert to avoid destroying nearby urban centers.
I got up from where I was sitting and went to make dinner. Mount Paozu truly has a vast variety of herbs that can be used as seasoning—wild mint, fine-leaf basil, and even a native garlic species with a mild, almost sweet aroma.
As I chopped up some mushrooms I'd picked earlier, I thought about how nice it would be to grow a small vegetable garden here. Nothing grand, just a few well-tended beds where I could plant peppers, chives, maybe some ginger. It would be more practical than going out into the woods every time I wanted some spice. But that's a plan for later, when I have more time and energy. For now, cooking already brings me a certain peace. It's as if, by stirring the wooden spoon in the pot, I also organize my thoughts.
After dinner, I sent Yamcha to bed. He was obviously exhausted, even though he tried to hide it. Goku, as always, seemed to have plenty of energy. I kept him with me for a conversation I'd been wanting to have for some time.
"Goku, has your father ever said what the strongest ability currently known to Saiyans is?" I asked.
It was something I wanted to confirm. Since Goku never lost his memory in this timeline, I figured Bardock might have mentioned something, even if only in passing.
"Yes," he replied matter-of-factly. "Father said we can turn into giant apes when we look at the moon. He said he'd show me how to use the transformation…"
"Did he say anything else?" I persisted, trying to extract as much as possible of what Goku clearly remembered.
"No, he didn't talk to me much while I was in that water-filled thing…" Goku said dejectedly.
It made sense. Bardock was never the affectionate type, he was the stern and grumpy type, or at least that's how I remember him from the content I had available.
"But Mom was always there!" he added suddenly, and his eyes lit up. "Sometimes she brought Raditz with her!"
I smiled at that; at least Goku's mother, Gine, seemed to have been an exception among the Saiyans, showing herself to be closer to the maternal demeanor I was accustomed to. We talked a little about his time on his home planet, his memories in the recovery tank, his mother's visits, and even the few smiles Raditz gave him. Despite everything, there was something precious in those memories, and I wanted to preserve that in Goku.
But the night wore on, and soon the subject had to change.
I looked up at the full moon slowly rising through the trees of Mount Paozu, and let out a silent sigh.
It was time to address what would follow.
"Goku, I know this is sudden, but I believe we should train this transformation skill your father mentioned…" I said calmly.
Goku looked at me, confused.
"Do I need to train this?" he said. "Why do I have to train this?"
I watched him for a few seconds, my grandson was surprisingly slow to grasp the consequences of this transformation. Forget about losing his rational mind, that was something only a few understood right now. Just the change in height and limb length would be a huge complication in a fight.
"The Giant Ape transformation isn't something you're used to," I said. "So if you try to use it in the middle of a battle without knowing how it works, your chances of losing will go way up, right?"
I was banking on Goku's competitive drive. I knew the fear of defeat would push him to do everything he could to avoid it, after all, he's incredibly competitive, especially as a child. Likewise, I could see the scowl on his face at the thought of losing for that reason; even the fur on his tail was bristling.
"Grandpa, let's train the transformation! I don't want to lose!" Goku said hurriedly.
It was scary how easy it was to motivate this child to do something.
"Okay…" I said. "Let's change seats first!"
This confused my grandson.
"Why are we changing places?" Goku asked.
"Do you want to end up stepping foot in the house?" I asked.
Was I being sarcastic with my question? Yes, I was. My grandson let out a nervous laugh, as if he'd suddenly realized he could literally destroy the house if he transformed into a giant ape. I don't blame him. That transformation was instinctive, brutal, and if he unleashed it uncontrollably, the consequences could be serious.
I decided to let the matter drop for now. There was still time to deal with the finer details.
I quickly entered the house, my mind already racing with what I would need for training. I grabbed some supplies and spare clothes.
As I gathered everything, I shouted to Goku
"Get ready and wait outside with Kintoun, we're going to need to go far!"
I heard the familiar sound of the magical cloud rising outside, and I smiled to myself. Even dealing with something as dangerous as an uncontrolled transformation, it was comforting to know that Goku was still, deep down, just a confident, curious child, ready for any adventure.
Goku and I cut through the night sky astride Kintoun, the wind whipping against our faces as the stars twinkled above us like silent witnesses. The full moon, round and bright, was already high in the sky, following us as if it knew exactly what we were about to do.
I guided my grandson to a secluded area in the heart of the Devil's Desert, an area where the ground was cracked and vegetation was almost nonexistent. With my proficiency in ki sensing, I confirmed that there wasn't a living soul for miles.
I landed first and looked around carefully. Not even animals ventured there at night. It was perfect.
"This is it," I murmured, more to myself than to him.
Goku came down soon after, curious, but without asking questions. His eyes still held that slight, childlike innocence, and for a moment, I doubted whether I was doing the right thing. But it was necessary. I looked at him seriously and said:
"Goku, look at the moon."
He hesitated for a second, then looked up at the sky.
(Narrator in 3rd Person P.O.V)
The little Saiyan lifted his face and stared at the great celestial body that reigned supreme in the night sky. The silvery light of the full moon bathed the desert in a cold, silent glow, making the dunes seem frozen in time.
At first, nothing happened.
"The moon is really beautiful, Grandpa!" said the little Saiyan with an innocent smile, his eyes reflecting the silver glow in the sky.
But before Gohan could respond, he saw it. The exact moment everything changed, his muscles tensed abruptly, like strings about to snap. The hairs on his tail and hair stood on end as if an electric shock had coursed through him. Even his heartbeat became audible and incredibly loud, intense, like war drums echoing in the silence of the desert.
Without hesitation, the elderly martial artist retreated a few meters. His feet firmly touched the sandy ground as he assumed a combat stance. His watchful eyes never left his grandson's, preparing for an inevitable confrontation.
As the old human prepared for the fight that would follow, Goku continued his transformation, his body began to expand, muscles became more voluminous, hair began to grow and cover his skin, his face began to resemble that of a monkey and his canines became sharper, his eyes, which were once bright and innocent, were now red and full of irrationality.
This all happened in just a few seconds, faster than Gohan's initial expectations, now the old man was facing an enormous beast, a giant ape that roared loudly in the middle of the inhospitable desert that surrounded them.
"Hehehe, the Great Ape is scarier in person than I thought…" said Gohan.
'The goal now is to get Goku used to the transformation... I have to hold him back until sunrise. Luckily, it's midnight. The sun should rise around six...' the old man thought, a bead of sweat running down his temple.
But his thoughts were interrupted when Goku, now the Great Ape, noticed his presence. Without hesitation, he opened his mouth and fired a massive blast of energy.
Gohan reacted instantly. He jumped to the side the moment he saw the giant's mouth open, narrowly escaping the ki blast. Giving the irrational Saiyan no time to react, the old man raised his own ki and flew at high speed, delivering a powerful kick to the creature's face.
The blow was accurate. The beast staggered, the impact leaving it visibly disoriented.
'His ki has grown greatly. His muscle volume and density are now unparalleled... But without a rational mind to guide this body, he'll be a predictable opponent...' Gohan thought. 'A strong opponent, but without skill... I can handle that!' said Gohan, steeling his will.
The Oozaru recovered and launched a furious attack on the small, elderly human. Thus began a relentless battle.
For hours, Gohan dodged, blocked, and counterattacked with precision. His every strike was calculated. Powerful. Well-placed. And even facing a creature dozens of times his size, the old master never backed down.
The fight dragged on under the starry sky.
Gohan no longer counted the hours. Time had dissolved into movements, dodges, blocks, and precise strikes that sought more to deflect the Oozaru's fury than to cause actual damage. He attacked the right spots: joints, articulations, the base of the neck, the side of the abdomen. But each blow, even well-placed, barely made the colossus hesitate for more than a few seconds.
And those seconds were all the old man had to breathe.
'The me from a year ago wouldn't have been able to fight for so long, I've gotten stronger, but if I have to repeat this every full moon I'll have to create something to keep me in this challenge more safely' Gohan thought as he dodged the huge fist coming towards him.
The more time passed, the more worn out Gohan became, the Oozaru's resistance seemed to have no end, it was only when the moon was very close to the horizon, threatening to set, that the old man had an idea, the Rozan Shoryuha he was recreating could knock him out or buy him enough time to rest and catch his breath calmly.
The ki blow that old Gohan was working on, no matter how powerful it was, still wouldn't be enough to create a serious or fatal injury to the target, it lacked the ki density necessary to generate this effect, now he needed time to concentrate the ki for his Rozan Shoryuha, 30 seconds were enough, and he knew exactly what to use to achieve it.
Quickly, Gohan used the Zanzoken, also known as the Afterimage Technique, moving quickly and creating illusions, he confused the great ape with the residual images, and when the beast least expected it, the old man appeared in front of his face with his hands near the center of his face with his fingers stretched towards his eyes.
"TAIOKEN!!!" shouted Gohan.
A blinding light filled the desert, intense as a miniature sun. The Great Ape's scream echoed violently, a mixture of pain and fury. The beastly form had sensitive vision, and the light had temporarily blinded it.
'That's it, it worked! I have to be quick now…' Gohan thought.
The old man wasted no time, as soon as his feet touched the ground he got into position and expanded his ki rapidly, his aura shone brightly and then gathered in his fist.
'My last test almost worked when I added a slight counterclockwise rotation… Now, I'm going to intensify that spin!' Gohan thought.
The accumulated energy swirled tightly around the old man's arm, reaching a point where it emitted a faint greenish glow, and then, when the great ape finally opened its eyes, it faced the old master with his attack finished, instinctively it tried to attack, trying to prevent the blow, but its body was heavy, and it was not fast enough.
In a peak of agility, Gohan performed his newest special attack, the result of days of testing and failure, inspired by one of the attacks he had only seen in cartoons in his other life.
"ROZAN…" Gohan shouted.
The energy in his fist shone even brighter.
"SHORYUHAA!!!" shouted the old man.
His fist swung out in an uppercut, and a massive blast of ki erupted, swirling in a violent spiral that surged forward and formed into the shape of a majestic dragon. The energy dragon collided with the great ape, its fur burning with intensity, the violent counterclockwise rotation cutting into its skin.
In the end, the dragon passed through the Oozaru's body and continued its course towards the sky where it began to disintegrate, leaving behind the imposing body of its opponent, he was motionless, but still breathing, the attack certainly did some damage and certainly fulfilled its purpose.
"It seems the technique is even stronger than I imagined…" Gohan muttered worriedly.
Despite knowing how incomparable the Saiyans' resilience was, he was worried about his unconscious grandson, as he had planned, still, this blow was extremely strong.
The hours passed. The moon finally disappeared over the horizon.
And the first rays of sun began to color the sky.
The giant ape shrank, becoming a child again, the clothes he wore before the transformation no longer existed, the fabric could not withstand the young man's rapid and great increase in height, now with nothing covering him, Gohan had to dress him with the spare clothes he had prepared for the occasion, the old man looked for serious injuries on the child, but apart from cuts and minor burns, the young man appeared to be fine and this drew a sigh of relief from the elderly man.
He picked up the child and flew home, Gohan was exhausted, he fought all night, and he wanted to sleep now.