Months after the defeat of Kid Buu, and Gohan stood firm in front of his current mentor, King Kai noting his strength and giving a frown.

"Are there any more lessons or pointers that you could give me, King Kai?" Gohan asked, weighted training gear barely notable by that point.

King Kai looked at him briefly.

"You've gotten stronger than before, and you've already mastered my techniques. At this point, there isn't much else that I can teach you."

"Really? That's a shame." Gohan crossed his arms, eyebrows furrowed. "Thanks for all the help so far."

"You won't forget our deal, will you?" King Kai asked, and at his aggression in asking this, Gohan raised his hands in a "calm down" gesture.

"I haven't forgotten! I'll use the dragon balls to bring you back to life, the first chance I get!" Gohan reiterated the promise that had allowed the Kai to agree to training him in the first place.

In spite of the events turning out for the better, as they often had when his father had intervened, Gohan had been wrought with a sense of inadequacy whenever he thought back to the day Buu had been released, as well as all that had happened afterwards, not least of all Earth being destroyed.

Though his power in his Ultimate state (or Mystic state, no one was quite sure what they were supposed to call it, not even the person who'd granted it to him) was enough to trump Gotenks even at his full power, as well as his father, as evidenced by the fights they had after the fact, the memory of his inability to step up when it mattered the most gnawed at his psyche, enough that he had sought out King Kai and the others to train under.

Under the tutelage of the four Kais, his powers had grown intensely in his normal state; in light of his Ultimate state supposedly functioning to put him at the absolute peak of his potential, later interactions with the Elder Supreme Kai rectified this, as he explained that his Ultimate state only brought him to the peak of the potential he had at a certain point in his life span.

Knowing that he would have had great power if only he'd applied himself prolifically to training, it acted as a secondary incentive for him to work at his hardest.

Now, however, mere months into the training, he'd found himself having mastered them all.

"Still, aren't you tired? You have to let your body rest up some too." King Kai warned him.

"I want to make sure that I'm as strong as possible." Gohan responded, before giving a sheepish smile. "Really though, it's been a lot of fun training under you. Thanks again, King Kai."

The North Kai smiled at him.

"Just don't forget your promise. That's all I ask."

Gohan nodded, then looked up.

"Could I ask you a small favor though?" Gohan asked.

King Kai agreed, and in the next few minutes' time, he stood on the Planet of the Kais, courtesy of Kibitokai, the Supreme Kai, teleporting him there.

"You said that you wanted to train under us?" Kibitokai asked as he looked to the much taller youth, Gohan nodding.

"Is there anything that I can do to keep getting stronger?"

Elder Kai chuckled.

"If you've trained with all of the Kais, I doubt there's much else that can be done for you, at least here." He lamented, before perking up. "That gives me a thought though — why don't you try your hand at going to another universe?"

"Another universe?" Gohan quirked an eyebrow, looking to Kibitokai for explanation, but when the Kai showed equal amounts of confusion, Gohan had half a mind to wonder if it was a joke.

"Neither of you know? Just what are they teaching kids these days." Elder Kai scoffed, both of them frowning.

"Isn't the universe everything in existence?" Kibitokai asked.

"Or... maybe another timeline?" Gohan asked, mind hearkening back to the entire debacle with Cell.

"No, no! This is just one of 12 universes in existence!" Elder Kai explained. "All the universes as a unit are called the Multiverse!"

"Huh?" Gohan and Kibitokai said in unison.

Elder Kai kept speaking regardless of this.

"To wit, each universe is part of a set of pairs — each one assigned a number that equals 13! If we go to Universe 6, it might be a place you can learn from too."

Gohan hadn't been entirely convinced, but figured it couldn't hurt to try.

"It's probably worth a look. It's hard to think that there are entire universes out there — it should be interesting, at least."

"Let's go then. I'll lead the way." Elder Kai reached his hand out to them. "I'll take you to Universe 6's Earth, for starters. Best to start with what's familiar before branching out."

They took the elderly man's hands, them being warped away in a flash of light.

As soon as Elder Kai teleported them to the surface of the planet in question, everything about it felt immediately different to Gohan, whose eyes widened as he felt a distinct pressure closing in all around him, enveloping him.

"What — what's this pressure?" He asked, voice a bit forced out.

"This version of Earth is a similar to yours, but different." Elder Kai explained, looking about. "While yours has life forms that have access to ki, in small, normal amounts, this planet has life forms that have a deeper, stronger form of ki, called divine ki. It's so omnipresent that you it can be felt in the air and soil."

"What's the difference between them?" Gohan asked, looking around himself, them being deep in forest, brimming with life, the sound of cicadas ringing out all around him. "I can't sense any energy from anything here. It's like swimming at the bottom of the ocean, where you can't see anything around you, but the pressure's closing in around you."

"That's exactly it. It's a more powerful form of ki, but one that normal people aren't able to sense easily. But even without being able to sense it, it doesn't take away from their ability to feel that it's there." Elder Kai strolled forward. "Let's try finding a settlement that you can train in."

Gohan shared a look with Kibitokai, who smiled with a shrug, them looking back to see the Elder Kai looking back to them.

"Come along now! You can't expect to get any better at this without moving."

The pair walked behind him with this, following the Elder Kai's path as they went.

A/N: I was originally going to make this another Gohan/Harem story, but I decided that if I did do that, it'd be after I'm finished with the main story, since it wouldn't exactly be appropriate in the interim of a war arc.

So not exactly in this immediate section of the story, at the very least.

As for the whole thing about divine ki being what made the equivalent of chakra, I personally just felt that it seemed like the logical step in logic to make, between the whole thing with Kaguya establishing how chakra and ki are not really the same thing at all (or at least don't follow the same logic beyond both being power meters that doubled as power levels).

Beyond that explanation, I felt making the Naruto Earth the Universe 6 Earth would have been fitting at least from the duality perspective; U6 Frieza is a conman who runs a syndicate where Frieza's a warlord, U6 Saiyans seem to be decent people and war heroes instead of space pirates (but don't all have Super Saiyan), the U6 humans being niche divine ki users that are well aware of how those powers function, and have shaky technological advances (Gigguk is right, I really have no idea how advanced Naruto is supposed to be), where U7 humans are sort of just super advanced sci-fi nuts that have no divine ki at all.

As for how Universe 6 got nuked and wiped of all life in the main Super timeline... I'm still not sure about how that happened, or how to explain how it happened by Naruto logic except for Toneri destroying everything or some other Otsutsuki popping up and doing that.