Here’s what happened in God Valley 38 years ago

• Garp wonders what to do with the kids and a marine tells him they’re property of the Celestial Dragons and should be taken to Mary Geoise, which makes Garp angry so the marine runs away.
• Garp decides to hide the children in his hometown under the care of his son, Dragon.
• The kids tell Dragon about their lives and about what happened at God Valley, causing Dragon to develop an intense hatred for the Celestial Dragons and the World Government.
• Dragon is inspired by Kuma’s desire to be a hero who could save people from suffering and grant their freedom and forms a group called the Freedom Fighters who attempt to grant people freedom using nonviolent methods.

• Dragon befriends Vegapunk and invites him to join the Freedom Fighters but Vegapunk refuses because they’re too poor to fund his inventions, so Vegapunk later joins the World Government instead.

• During their travels the Freedom Fighters come across some Devil Fruits and Kuma tells Dragon how the Celestial Dragons would force their slaves to eat Devil Fruits to amuse them, so Dragon tells him they’re pacifists who have no need for any powers so they won’t eat them but might be able to sell them to help fund their operations.
• After the Ohara Incident occurs, Dragon realizes nonviolent methods aren’t enough and decides he has to wage war against the World Government to truly liberate everyone, so he forms the Revolutionary Army together with Kuma and Ivankov.

• Dragon and the others eat the Devil Fruits they found and resolve that instead of aspiring to be ‘heroes’ who grant people freedom peacefully, they’re going to become ‘devils’ who’ll free people by crushing their oppressors.
• Since Dragon and the others have no combat experience they’re still weak even with their new Devil Fruits, so they decide that instead of trying to fight the oppressors by themselves they’ll only help nations where the citizens are willing to fight alongside them.

• The nations helped by the Revolutionary Army are extremely grateful to them and rulers of these nations are glad to provide them with money and supplies, and many of their citizens are eager to join them to help liberate other countries.
• The World Government hears about the actions of the Revolutionary Army, causing their members to gain large bounties and Dragon being named the World’s Worst Criminal.
• Kuma successfully liberates a nation called Sorbet Kingdom but its king was killed so the citizens choose Kuma to be the new king.
• Kuma makes Sorbet Kingdom his home and has a daughter there with Ginny.
• The World Government finds out about Kuma being at Sorbet Kingdom and sends CP0 agents there.
• CP0 tells Kuma that as former slaves he and his wife are the property of the Celestial Dragons but considering he’s the ruler of a World Government-affiliated kingdom they’d be willing to take his daughter as a substitute for him.
• Kuma and Ginny try to fight off CP0 but are outmatched and Ginny is killed.
• CP0 tells Kuma they’ll leave his daughter alone if he agrees to do everything they ask him to do, so Kuma reluctantly goes with them and agrees to take part in their ‘human weapon’ experiments.

• The World Government knows it would look bad if the world finds out what they were doing to the ruler of one of the World Government Kingdoms so they have the news report that Kuma was a horrible tyrant in Sorbet Kingdom and willingly left to become a pirate, and they decide to add him to the Warlords to prove the story of him being a pirate is true.
• Kuma is instructed to go to Egghead to participate in their ‘human weapon’ experiments and knows he will completely lose his sense of self due to the experiments, so he uses his Devil Fruit powers to extract his memories and asks Vegapunk (who he trusts since he’s a friend of Dragon) to store them somewhere safe so he can potentially be restored later on.
• Kuma also brings Bonney along to Egghead so he can have Vegapunk implant a monitoring device into Bonney (along with a GPS system into Kuma’s brain) that would alert Kuma whenever Bonney is in danger and allows him to know her exact location at all times.

• Kuma also had Vegapunk implement one order in his brain which would override any other orders he receives, and that order is a simple one: protect Bonney.
• The flashback ends with Kuma appearing on Egghead and rescuing Bonney from Saturn and the marines.

We already knew some of this stuff so I’m largely just connecting the dots to fill the gaps in our knowledge.

*Theory by NewCanadianMTurker