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Prologue: Kami's Job!
There are gods in charge of monitoring individual planets called the planetary gods. God of each planet is selected among the pure-hearted beings in the sentient life forms of that planet.
Attendants from the afterlife are dispatched to assist these gods picked among the natives. The purpose of this system is to oversee and protect the sentient life-forms of each planet and more importantly, to hasten the racial development of immature sentient species, guiding them towards the greatest happiness. The attendant sent from the afterlife are only permitted to act in a subservient role to the planet's god, on the idea that a species' fate ought to be entrusted to the species itself.
The job of the planetary god is travelling to and guiding some specific souls to the other world. They are long lived and have the ability to see and sense events around the world. They are bestowed with God-ki and have the ability to sense gods.
Thousands of years ago, when the saiyans used to live on their home planet Sadla, seeing that the saiyan race was doomed to racial regression and destruction, the planetary god of saiyans was requested by her apprentice to fight on the behalf of the good saiyans. But, as she was no fighter and was also not supposed to take the fate of the planet in her own hands, she denied the request.
Been taught the secrets of the God-ki by the saiyan goddess, the apprentice decided to use it in order to transform into the first Super Saiyan God and defeat all the evil saiyans. As he wasn't bestowed with God-ki yet, he came up with a ritual to transform.
But, he soon ran out of power and this turned out to be a fatal mistake. The strongest five pure-hearted saiyans were already weakened after the ritual. As a result, the good saiyans lost the war and most of them were wiped out.
Distraught, the saiyan Goddess decided upon destroying the planet with a meteorite shower. (*)
Most of the saiyans had to flee their planet and make planet Plant their new home planet, which they later named planet Vegeta.
Having watching the evil within the saiyans grow, the saiyan Goddess had already acted behind the scenes to prompt the flash of paranoia that inspired Frieza's attack on the planet. (*)
In Age 739, Beerus, the God of destruction, was told a prophecy by the oracle fish that in 17 years he would face an opponent called the Super Saiyan God who could entertain him endlessly on a planet filled with delicious food. After he was told this, Beerus went into a deep slumber.
-XXXXX((Present Day, Just after the 23rd martial Arts tournament))XXXXX-
"Goku, you've proven yourself worthy. In fact, I'd like to offer you my job. Will you take my place as the new Kami?"
"Ah…Me? A Kami? Are you serious?"
Nodding his head, the current Kami continued " I've the utmost confidence in you. It could be your greatest adventure."
"No-no-no-no-no! I couldn't! I appreciate your confidence in my abilities, but that's not the future I'm looking for. It's your job, keep it! I would die if I had to stay there! It's so boring!"
"Don't be hasty" Kami slowly continued, "Listen to me, Son! Kami-sama! You can become Kami-sama! Think of all the good you could do with the power! You are the only one I could trust to succeed me. Only one who can take over what I have left behind! What do you say?"
Goku was thinking about teasing Kami and call the flying Nimbus in order to fulfill the promise that he had made to Chichi, when the group heard a voice from the sky.
"I'm sorry, but looks like you don't get to say in the matter."
Before anyone could figure out where the voice came from, they saw Kami get down on one knee as he yelled at everyone to do the same.
With everyone down on one knees, he responded to the voice "You must be… the great overseer… King Kai! Sir, what do you want from us?"
"Listen very carefully to what I have to say! Not far from now, Bills, the God of destruction will arrive on earth!"
"God of destruction.." Goku wondered out loud," Sounds really strong! Kami, why haven't you told me about him? And who is King Kai?"
"King Kai is one of the great overseers of the world. As for the God of destruction, this is the first time I'm hearing about him" whispered Kami to Goku.
At this, King Kai yelled at Goku" If Bills arrives, do not do anything to upset him no matter what happens! If you do, the whole earth would be destroyed!"
The group slowly swallowed hearing those words.
"Earth destroyed?" asked Roshi, not believing what he just heard.
"Yes, I beg of you! The fate of the earth is in your hands!"
"What does he wants from us? Is he coming here to destroy something? And what does it has to do with Goku becoming the Guardian?"
"Listen carefully! I can't tell you in much details at the moment, but Goku needs to become the guardian in order to greet him before he comes. You must prepare all kinds of most delicious food to him. And make sure to keep him entertained till he leaves the planet. You see, he's a fickle and fearsome god. He governs the destruction in the universe, and destroys planets and races at the slightest insult."
"Like someone not picking up after walking their dog?" asked Puar.
"Well, I guess so."
"Like someone not eating everything on their plate?" asked Chiatzou.
"Well I guess so."
"Like someone pissing in the spring?" asked Oolong.
"Yes, that's right" said the irritated King Kai," When he awakes, he destroys tons of worlds till he gets sleepy!"
"Doesn't that makes him the bad guy?" Krillin couldn't help but ask.
Shaking his head, the kaio replied" That's not so. He is a god. To enable balance and harmony, if there is are gods that create, there will also be gods that destroy. I'm begging you, please try your hardest not to do anything stupid. Got it?"
"Okay. As long as he doesn't does anything bad, I'll keep away!" promised Goku.
King Kai sighed, knowing that Beerus would go to Frieza first and then come to him. He hoped that everything goes well, otherwise Beerus might make his planet even smaller... about the size of his shed!
After some time, the group came up with a plan. Goku and Kami would head straight up to the lookout for the ritual, while Bulma would go to the Capsule Corp. to help Chichi and the Ox-King arrange a wedding below the Korin's tower. All the rest of the fighters in the group would go along Bulma to Capsule Corp. and then set to seek out the dragon balls with the dragon ball radar.
A/N: Wow, this took me less than a day to write!
Footnotes(*): 1. In original canon, King Kai tells Goku that the saiyan's were so evil that their guardian of the saiyan's planet killed them using meteorite shower.
2. The Guardian acted behind the scenes to prompt the paranoia, something Goku briefly alluded to when he, after becoming a Super Saiyan and confronted with the atrocities the saiyans committed, replies that "the saiyans paid for their mistakes!".
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