Now, before the show ever premiered, I was determined to mine it for ways in which it may be able to tie in with Adventure Time,
Bravest Warriors, & Be and Puppycat, shows which are in no way confirmed, or even suggested really, to share one universe. However, all four shows have ties to Adventure Time, arguably the biggest established universe. Pendelton Ward being the creator of Adventure Time and Bravest Warriors, Natasha Allegri, a former writer for AT, is the creator of B&P, and as mentioned before, Rebecca Sugar was a storyboard artist for AT but left to create SU. So in my mind, that makes it more likely that, while they may never make a huge crossover, I can see them putting in threads. In this journal I'm going to go over both my own ideas and potential evidence in the shows themselves; maybe a 60/40 split.
First, in Adventure Time, we know that a little over 1000 years ago, an event known as the Mushroom War happened, in which most life on earth was annihilated, and mankind eventually mutated into all manner of species, several denizens of Ooo. The most obvious connecting factor would be that the other three shows take place at different points in a single history relative to the Mushroom War. B&P is the immediate present, and SU is sometime around it as well. BW is an interesting subject. BW takes place on Mars, and features advanced technology, space travel, and commonplace interaction with alien life. I've heard people suggest that colonizing Mars was pushed forward when the Mushroom War was in its infancy, and I think for a connected universe this makes sense. Once away from Earth, which is becoming increasingly consumed by warfare, the colonists of Mars devote themselves to scientific advancement and exploring the universe. Earth is eventually annihilated by the war, and Mars thrives, getting to the point we see at the start of Bravest Warriors. Furthermore, and here's the kicker, we see in the episode of AT 'Sons of Mars' that Mars is habituated by "martians", who are humanoid and seem to be a highly advanced species, referring to their civilization as as “utopian, super society". What if mankind evolved peacefully on Mars, and after the 1000 or so years since the war mankind turned into the martians we see in 'Sons of Mars'?
One more point about Mars before moving on. On Ooo, the terms "Grob", "Gob", "Glob", and "Grod" are used interchangeably for what seems to be some sort of common deity. Again in "Sons of Mars" we see a very powerful being known as Grob Gob Glob Grod, four personalities in one body, who is shown to be able to come to and from Ooo from Mars with relative ease. In the episode "Too Young", a character remarks they don't know where food comes from, and another character responds, and I quote, "food comes from Mars." They are silenced before they can elaborate, but what if Grob Gob Glob Grod is seen as a deity because he supplies Ooo with food?
Now, we see in B&P, other dimensions seem to be plentiful, and we see from the being "TempBot" that there is at least some system in place of taking care of threats from other dimensions. What if the Crystal Gems are the Earth version of this? What if magical and extra-dimensional beings occasionally seep into our world, like Electric Skulls and Centipedles, and the Crystal Gems are there to keep them contained and protect us from them? That's why magical/weird creatures aren't more common, the people of Beach City are just used to it due to the proximity to the Gems. It's implied in the AT episode "Finn The Human" that the Lich was present during the Mushroom War, and may have been the cause of it. What if he was an evil magical being that either wanted into our world or wanted more magic in the world, but the Gems stood in his way? What if he either started the war or perpetuated an existing one to keep the Gems occupied, since the war threatened the world and they're its protectors, magic or not? Eventually the war escalates too far. The Gems fall in battle(sad, I know, but bear with me!), yes, but the planet is too badly damage, and the being that would eventually become the Lich is almost destroyed by his own machinations. It took him centuries to regain his power, while the Land of Ooo forms around him. The many mutated species that arose from the radiation mingle with all the magical creatures, good and bad, that come through now that there's no one stopping them. The presence of magic even helps the planet along in its evolution.
When the Lich is finally ready to make his move, he finds opposition from the hero Billy. He destroys several kingdoms, including the Candy Kingdom, before Billy "casts him down". The Candy Kingdom rebuilds, despite only a handful of its citizens surviving. One young girl is tasked with being its immortal ruler, creating new candy citizens, and leading reconstruction efforts, as we see Princess Bubblegum do in "The Vault". She then works with Billy to trap the Lich in amber and seal him away forever.
My final point: after news of the war reaches Mars, the Courageous Battlers, parents of the Bravest Warriors and then protectors of Mars in the way the Crystal Gems are(or were ) of Earth, grieve over the news of their death, and decide to honor them by...........creating their own gems they wear on their body that emit a weapon! Yeah, that's right. BAGOW!
So, that's my pitch. Is it a stretch? Maybe. Do I have no life? Absolutely. But what do you guys think about my ideas? Stuff you agree with? Stuff you don't? Anything you can think of that I missed I'd especially love to hear! So go forth, comment all the comments and be children of the fandom!
PS Alternatively(it only just occurred to me xD), we know Bravest Warriors takes place in the early 3000s, and its implied the Mushroom War occurred in the first half of the 21st century. So maybe the martians weren't humans. Maybe they're just a separate species that coexists with the humans who colonized the planet. Maybe they even took the humans in after they were fleeing from the Mushroom War and shared their cool technology. Point is, if this is true, that means the years for AT and BW could sync up, which would explain why there are still humans around to give birth to Finn, despite them supposedly being absent for so long. This would also lead credence to......
PSS This was partially inspired by a lovely person who some time ago came up with a similar sized theory on how Beth and Chris, two of the Bravest Warriors, might be Finn's parents. Its about as solid as what you see above, but it feels wrong leaving it out of a piece dealing with the connection between these universes, so you can read it here: www.deviantart.com/art/Finn-s-… I encourage you to check it out