Comments and (hopefully constructive) criticisms are welcome. Enjoy the story.
This is a flashback
"This is Gohan thinking"
Chapter 4: Realization
The trip to planet Sadala was short; it was almost as far out in the boonies as Earth. In Bulma's newly designed spaceships they arrived after only a few hours. Gohan made the trip with his wife and daughter, while Goku had ended up with the two female saiyans. Vegeta had been unable or unwilling to shake off his apprentice hopeful, so he and Cabba traveled together. That left only Frieza and Whis, who had also decided to come along, Whis to sample saiyan cuisine and Frieza for some unknown, probably evil, reason.
They arrived on a planet that appeared remarkably earth-like outside of the 10 times earth gravity and lack of a moon. A small crowd stood waiting for the arrivals. As Gohan stepped off the ship, a curious Pan cradled in one arm, he studied the universe 6 saiyans. There really wasn't all that much to differentiate them from humans; they didn't have tails and their builds seemed more or less normal, if a bit more fit and muscular on average. The only real tell was the raven hair and obsidian eyes- although there were exceptions to that rule; apparently there was some intermingling with other races.
The crowd parted as a regal figure walked up, clothed in an outfit similar to Cabba's but red, and more ornate. The man bowed to Whis, and spoke in a commanding baritone. "It is an honor, brother-of-Vados".
Whis bowed in return, smiling slightly. "Likewise".
The man looked somewhat like Gohan's mental image of the old King Vegeta, goatee and all. The hair was off, though, and his eyes less angry than Vegeta's. He wasn't as strong as Gohan, his father or Vegeta, but he commanded a subtle confidence that went deeper than strength. This was a man who earned the loyalty and respect of his people rather than taking it.
The yet-unnamed king turned to Gohan. "I am King Tarble. I cannot sense your energy, and so I presume you are universe 7's Lord Beerus. It is an honor". He began to bow, but paused. "Though, I have to admit I don't really see the resemblance between you and your brother…".
Gohan laughed, hand behind his head as usual. "That's because I'm not Beerus," he explained.
"Gohan here is one of the last universe 7 saiyans. Well, a half saiyan, to be exact. You were right to assume he possesses god ki, but that was the result of training, not godhood".
The King looked at Gohan, considering. The half-saiyan grinned and continued rubbing the back of his head. Finally the King spoke. "I shall be interested to hear how that happened. In the meantime," he said, looking around the group of visitors, "why don't you all get settled in? I'll have servants show you to your rooms".
…
"I can't believe anyone would want to run a saiyan nursery, that sounds like HFIL!" exclaimed Videl, as she and Gohan followed an attendant to their room.
Gohan laughed. "I can't disagree with you there. I'm just glad for a little break". They walked into the room. It was sparsely decorated, really just a large bed, a few chairs and a large window with a view of surrounding fields. The door closed behind them, the attendant remaining outside.
The two looked at eachother. "It's been a while since we had some alone time, hasn't it Gohan," said Videl, blue eyes smiling. Gohan's heart rate began to increase. He grabbed her by the waist and pulled her close, causing her to gasp a little. Their lips met and her hands tangled in his hair. He picked her up and walked over to the bed.
…
By the time Gohan and Videl emerged, Goku and Caulifla had, of course, already fought. Kale had been content to remain on the sidelines this time, so Goku ended up winning easily enough. As they walked onto the sparring ground Goku was in the process of demonstrating SSJ 3 to an awestruck Caulifla. Kale and Cabba also watched, although their reactions were more subdued.
Gohan looked around, then noticed Vegeta standing next to him. "Hey Vegeta, I've been meaning to ask-"
Vegeta cut him off with a disgusted noise. "What, more questions? Are you going to pass out again, if I answer?"
Gohan was content to simply ignore the mockery, but Videl butted forward angrily, shaking off the hand Gohan laid on her shoulder. "Vegeta, where do you get off insulting Gohan like that? You mock him when he doesn't train during times of peace, then you mock him again when he does train! You had better answer his question".
She said the last in an ominously quiet voice. Vegeta seemed caught between his desire not to back down, and some racial fear instinct all the saiyans seemed to share. He contented himself with a simple harrumph and turned away.
Gohan interpreted the movement as an invitation. "I wanted to ask, why didn't you ever go SSJ 3? There were a few years after Majin Buu when the only way you could have caught up with my dad was by transforming. So what stopped you?"
Vegeta seemed to have an internal struggle, but whatever it was it resolved itself after a few seconds. He sighed, and turned to Gohan. "I was just as strong as your father in my base form, perhaps even stronger, so strength wasn't the issue. I tried many times, but it always took too long. I always ran out of energy before I could complete the transformation. I suspect the only reason your father can do it is because he gained control of SSJ 3 while he was dead- the body is more durable when you're dead, for some reason".
Gohan nodded. "Interesting". "Thank you Vegeta, that's all I wanted to ask".
Vegeta's grunt could have been an acknowledgement or a dismissal, possibly both. He turned back toward the grounds, where Caulifla was now attempting to transform to no avail.
They all watched for a while as Goku attempted to tutor the eager saiyan girl, Gohan and Videl laughing at Caulifla and Goku's antics while Vegeta remained stoic. The two had gathered quite a crowd. One saiyan, an older muscular man with short jagged hair, requested a lesson on turning SSJ. There was a chorus of agreement from the rest of the group, although Caulifla growled in irritation.
Gohan turned to Videl. "I think I'll go find the King," he said. "I'd be interested to learn a bit about universe 6 saiyan history".
Videl nodded. "I think I'll stay and watch a little longer," she said. "Let's find each other before dinner time".
Gohan nodded back, then walked off, an attendant joining him.
…
"Every child on Sadala has heard many stories that tell of super saiyans," said the king. He and Gohan walked along a well-worn path, the sunlight dappled by clouds and a slight breeze rustling through their hair. Pterosaur-like mammalian creatures darted through the air, occasionally attacking one another with brutal claw slashes. "There are many different variations: super saiyan, Ascended, Legendary super saiyan, Super Saiyan God, Limit Breaker… I had always assumed these were all names for the same form. But now it is clear to me that that is not the case. At some time in the past my people were capable of some of the same transformations you universe 7 saiyans now use".
Gohan nodded. "You know, it's almost ridiculous how many transformations there are. Over the years we just keep discovering more".
The King chuckled. "It is a bit strange," he admitted. "Now that you mention it, it is very strange that saiyans should be capable of so many different transformations. Why not a single form? But no matter. Why don't you tell me about this 'training accident' Whis spoke of earlier?"
…
Over the next few days, Gohan enjoyed himself with Pan and Videl, had a sparring match or eight with eager young saiyans, and gorged himself on saiyan cooking, which was unexpectedly good- they seemed to have learned from the newly restored earthlings. But his conversation with the King remained in the back of his mind. He couldn't stop thinking about all the different forms he'd seen saiyans assume: the various super saiyan grades, super saiyan blue, Vegeta's further ascended form, super saiyan red, and his father's mysterious form from the tournament. It was during the dinner feast five days after their arrival that Gohan's musings seemed to come to a head. As he gorged himself, the different forms swirled around in his mind, begging for his attention. He tried to focus on his food, but, for once, he just couldn't. "What is the common factor? The forms have to be related somehow! Think!"
His father, fighting with Frieza. His valiant efforts were in vain; the space tyrant was simply too strong. Then, the first transformation, driven by need and triggered by anger. Suddenly Goku had the power to crush the previously untouchable lizard.
Fast forward.
Gohan stood near Cell, guilt tearing him apart as he watched his friends being beaten for his weakness, for his inability to fight. Then, a few words spoken by a broken android. The gentle giant, crushed under Cell's foot. This man, who had chosen to protect the world against all odds, was gone, and he could never be brought back because he didn't have a soul. Another transformation, driven by need and triggered by anger, and Cell could do nothing against the oncoming storm of Gohan's power.
Further.
At a moment when the fate of the world hung on a mortal's ability to become a god, six saiyans came together and Goku transformed.
Two saiyans who had to learn how to use god ki on their own, training. Their fists connected, and a flash of blue aura rippled through the air.
Vegeta, about to face off against Jiren. Super saiyan blue wasn't enough, so he went further.
And finally, back to Goku. He faced off against a being with unimaginable power, power he could not match even with the Kaio-Ken. In the moment when he needed it most, he transformed, and shocked the gods with his Ultra Instinct.
"What's the common thread?"
Think.
His father's words echoing in the time chamber all those years ago. "The power comes in response to a need, not a desire!"
Gohan paused, a drumstick frozen halfway between the plate and his mouth.
Whenever they had needed more power, the original super saiyan transformations had emerged. When they needed the ability to use god ki, they discovered super saiyan blue and red. When his father needed to use Ultra Instinct, he had adopted a new form. It was almost like… all these forms were extensions of the same ability; they were all variations on Super Saiyan.
Saiyans didn't just have a bunch of random, built-in forms for every situation; they had the ability to create new forms in response to a need. And this ability was the true "Super Saiyan" of legend.