All rights belong to Akira Toriyama, Toyotarou and Toei Animation
This is based on the manga cannon, so there may be some discrepancies with the anime.
Early morning was the perfect time for Goku to sneak out of his house (and away from his wife) for some training. Chichi was insisting that, now he was home, he should be working on the farm and earning money to support his family.
He liked Goten and all, but Goku was really looking forward to the first chance to get away. Maybe he could sneak back with Whis again. Chichi wouldn't find out until it was too late.
Speaking of Whis, though, he could sense three familiar people on their way towards him.
Were they going back now? There'd been no indication of a quick get-away but Goku wasn't one to look a gift horse in the mouth.
"Hey guys!" He called out, waving as they descended to meet him. "Are we going back now? Just don't be too loud because Chichi's still asleep."
He looked a little shifty-eyed, "I don't want her to find out and stop me."
Sometimes he was really jealous of Vegeta, whose wife was incredibly rich and didn't seem to mind his disappearing act. If anything, she seemed happy not to have an overbearing husband, whereas Chichi definitely wanted Goku around more often.
Goku had thought with Goten older and Gohan starting his own family, he would not be expected to be so hands-on. Man, was he wrong, to his bitter disappointment.
"We have a situation," Beerus interrupted his thoughts.
"Another problem?" Goku tilted his head to the side, hand on his chin.
"Yes."
"We were hoping to use your expertise." Whis expanded.
"Mine?" Goku asked, looking at Vegeta, who turned his head aside with a scowl.
"This sealing technique of yours, the mafuba."
"What about it?"
"We need to use it. It seems that when you returned from the erased timeline, more than Lord Zeno came back with you." Whis elucidated.
"Huh?"
"Perhaps Vegeta can explain to you on the way. Are you prepared to come with us?"
"Of course!"
Vegeta made sure that Kakarot had all of the right equipment this time. He did not want another repeat of the discount token incident. After explaining all that he knew about the situation, which was not all that much, he had to admit, they had graduated to discussing other things as Whis towed them across the galaxy.
"How do you get Bulma to agree with your training?"
"What do you mean?"
"She doesn't seem to get upset like Chichi."
"I'll admit she was a little disappointed to have me away for long stretches of time."
"It's not just that, she lets you train in the gravity room when you're home."
"I have never understood your wife's intransience. Bulma knows exactly who, and more importantly what, she married. Training and fighting are as important to saiyans as food. Bulma has studied my physiology in detail. She knows this. I'm surprised your wife still insists on expecting you to behave like a human. We aren't. Bulma is quite aware that she married an alien."
"I guess. I don't feel like an alien, though. I just like to fight, that's all."
"And have you noticed that same attitude among our children?"
"Well, not really, no. Gohan's more of a scholar, and I think Goten just likes to roughhouse, like a little boy would."
"Likewise. Trunks does not have the innate desire to fight, train, and become stronger. What he does is to impress me. You and I, we are different to anyone else in this universe."
"Huh. Seems kinda lonely."
It certainly was. And it made Vegeta very glad that Frieza was dead.
He did not voice his thoughts, instead turning back to face wherever they were going. Space was flashing by in an impressive array of colours as Whis and Beerus travelled faster than light. Vegeta hoped that he could one day match such speed. No, not hoped. He would.
But he was worried about what was coming. Vegeta had changed, as a person. He had become the man that Bulma wanted to be married to, that Trunks was proud to have as a father. Well, Trunks had been proud of him before, but he shouldn't have been.
Vegeta did not want to lose that. He knew what prolonged exposure to the Darkness had done to the saiyan race, turned them into monsters. It wasn't something he could risk. He wasn't sure how long it took for the poison to take effect. They would need to be as quick as possible.
Vegeta did not want to go back to being the man he had been.
"There it is," Beerus commented as a blanketing fog appeared in the distance.
"It certainly has grown since we last visited." Whis commented.
The Great Darkness was everything Vegeta had expected. It engulfed the stars, swirling out in all directions and enveloping everything in a black haze like the dust storms on Frieza Planet 3. It reverberated in sync with the darkness within his own soul, each calling out to each other like long lost brothers. He felt drawn towards it, as if by a magnet. And the darkness within him was singing, almost literally singing as they hurtled towards one of the greatest threats in the known omniverse.
He hadn't thought that they might interact.
Why hadn't he considered that? But it was too late for second thoughts. He would just have to manage. He had plenty of practice fighting against things within his own mind; the Darkness, his own saiyan instincts, both normally and as a Great Ape.
"That's it?" Goku asked, "That mist? Can't we, I don't know, blow it away?"
"To where?" Beerus grouched.
"Oh. I guess that would be a problem."
"We'll touch down at that planet there. Hopefully it isn't inhabited."
They were in luck, as nothing approached them as they landed. Vegeta couldn't sense anything nearby, certainly nothing powerful. Nothing even human level. But the atmosphere was breathable, perfectly hospitable if a little cold. Vegeta did not like to consider what that might mean, but he did. It was highly likely that the inhabitants had wiped each other out. That had been common eons ago when the Great Darkness first emerged. Through the haze, Vegeta took in a planet of drooping vegetation, with looping vines and bent trunks. The ground beneath their feet was a rich blue, almost a royal blue. Not that blue had been the colour of royalty on Planet Vegeta. No, only the colour of freshly spilt blood would do for a warrior kingdom.
The blue soil dusted Vegeta's pristine white boots as he made his way to the centre of the clearing they had landed in. The ceramic pot in his hands was delicate and chipped, a completely unsuitable prison, but he had been assured that the material did not, in fact, matter for the technique. Handing the seal to Kakarot with a glare that said this time you'd better do it right, Vegeta backed away to stand next to Beerus and Whis.
"Hurry up!" Beerus barked, making Kakarot jump like a buffoon.
"Indeed, it is best to minimise our exposure," Whis agreed.
"Okay, just let me concentrate," Kakarot replied, and Vegeta noted some tension in his voice. Was it affecting him already? How long would it take to change them?
Kakarot shuffled into position, Vegeta watching closely as he had not been able to before. The stance was simple enough, but Vegeta wasn't sure what Kakarot was doing internally. Then he felt Kakarot's power split the air like a knife as he began pulling the Darkness towards him. A shrill wind picked up, howling through the trees and whipping Vegeta's gravity defying hair. The air around them thickened rapidly, until Vegeta could not even see Beerus next to him.
Why don't you kill Kakarot, while he's distracted?
It was sudden, insidious, and definitely ridiculous. A crackling voice reminiscent of his own echoing within his mind. It was familiar, but never had been so strong. Except for that one time with Babbidi.
But he certainly wasn't going to give in to it.
He could feel it, like the Great Ape's instincts, clawing at his consciousness, trying to assert dominance. His face screwed up in concentration as a battle began within the walls of his own mind. Fortunately it didn't last long.
The entire process was much quicker than Vegeta had expected, given the large surface area over which the Darkness was spread. In fact, after only a few minutes Kakarot, sweaty skin glistening in the newly revealed sun, was slapping the seal over the innocent-looking pot and stepping back.
Vegeta saw his legs shake, and rushed forward to catch him as he fell.
"Phew," the other saiyan panted, "That sure took a lot out of me."
"What should we do with—"
BOOM!
Shards of pottery flew everywhere as Darkness spiralled out of its container, shooting off in all directions like a malicious cyclone.
"What? How?" Kakarot blinked.
"Oh dear." Whis commented, and Vegeta felt that he meant it.