Thread by @Herms98

Age 461: a year after Roshi’s birth, Katatz’s child meets with the God (Kami) of Earth, becoming his apprentice. 30 years later, Katatz Jr is all set to take the title of “Kami” as his own, but rival candidate Garlic (descended from Makyo stock) has his own ideas. #HistoryofEver

But Katatz Jr isn’t in the clear yet: during his 200 years on Earth, interaction with humanity has allowed a trace of evil to seep into his benign Namekian nature. To correct this defect and become worthy of the name “Kami”, he takes drastic measures. More on this next week...

Prior to the big split, Katatz Jr relies on his Namekian racial memories to have a go at making dragon balls. It’s a good idea, but poor execution: the balls have black stars (a real turn-off), scatter throughout all of U7, and destroy the planet if not reassembled within a year.

Katatz Jr tries to erase this failure from history by sealing the balls up deep within the heavenly lookout, along with...a bunch of skeletons? God alone knows where those came from. Maybe they’re all the guys who drank Karin’s death water.

This of course is the backstory to the black-star dragon balls that kick off GT. The GT Perfect File Vol.1 explains that the whole “destroy the planet” thing is a direct side-effect of the ball’s immense power, something kinda/maybe implied but never stated in the series outright

Kaio apparently knew about the black-star balls all along, but didn’t think they were still around, and also didn’t know they’d destroy Earth until doing further research. He’s right up there with the Galactic Patrol in terms of sloppy follow-through.

In DBZ Movie 1, Kami says that Garlic’s rebellion was 300 years ago, and so the Daizenshuu 7 timeline dates it to Age 461, exactly 300 years before the main events of the movie in Age 761, the same year Raditz comes to Earth.

The Daizenshuu 7 timeline also provides Age 431 as the year Katatz Jr becomes apprentice to the prior God of Earth. As far as I know, this specific date isn’t based on anything said in the series. As already noted, this puts the length of his apprenticeship at 30 years.

The exact timing of the black-star balls’ creation isn’t specified, beyond the fact that it was prior to the Kami/Piccolo split. But since they are sealed up within the lookout, it would presumably be after he arrived there and became Kami-in-training.

Tomorrow: it’s a small world after all!