*The Great Keyblade War being pretty much the Time War from Doctor Who levels of
inconceivable horror where many factions of Keybarers fought for supremacy and ownership of the universe, each day bringing attrocities beyond comprehension that made the previous days horror seem tame in comparison. It all ended when Xehanorts teacher
Kao-Cen-Darach and Doctor Ludwig Von Drake created a weapon called The Mass Shadow Generator and told the many factions it would strip them of their powers permanently. He, of course, lied. All it did was strip the souls from the bodies of everyone who came to his Hollow Bastion to stop him. His rational being that whoever didn't come to stop him were those ready and willing to lay down their weapos and accept peace. This worked and the only keybarers left were Mickey, Donald, Goofy, Xehanort and Maleficent. Maleficent, who went to stop Darach, but arrived just a little too late, saw the creatures left behind after the Mass Shadow Generator and took them as an army of her own to conquer the universe. Which is how things got so bad.
*Maleficent's first conquest was her own world, where she locked it into a time-loop where every 16 years, she wins and then the clock resets so she can forever keep reliving her greatest victory. She has imprisoned Flora, Fauna, and Merryweather to force them to watch it over and over, so
YRP had to take over raising young Aurora to defeat Maleficent, giving her access to Dress-sphere power.
*Mickey, Donald and Goofy are living in the multiverse having sealed away their memories and powers in order to not lure the Heartless to them. Mickeys father was the Mad King who he overthrew during the Keyblade War and imprisoned him away in Memoria (The realm of Memories) Donald was a one-man war-crime, a man of unfathomable power but used it for good... Except that time he fought in WW2 and the US Government had to make up some nonsense about "Atomic Weapons" In order to cover up Donalds use of a couple of Xeta Flares on Japan... And Goofy is actually a stone-cold badass who locked away his badass persona in order to allow the fun-loving side of him to serve as a better role-model for Max as they lived together.
*Max Geef is also capable of controlling the Heartless. This is why Goofy and his friend Pete have been sealed away in a custom built realm (Goof Troop world) where Max can grow up safe and sound and not have to deal with the horrors of the universe, because Goofy knows that, if Xehanort finds out about Max's power, he'll try to turn Max into a weapon. Pete is essentially Goofy's Handler, there to keep Goofy and Max's lives interesting and bring back the badass if anything goes wrong and raising his own family.
*St Bega breaking away from Xehanort along with the other Hero-based Heartless in order to enact their own Anti-Heartless plan. Taking over the universe and turning it into a war-industry to dedicate every resource in the universe to fighting the Heartless. To this end, they kidnapped a bunch of characters who have power of dominion over things and gave them some old weapons from the Keyblade War, the
Hammers of the Worthy (Max Geef became Xam, Breaker of Shadows. Antonio Madrigal became Oinotna, Breaker of Beasts. Eiko became Okie, Breaker of Spirits. Experiment 624 "Angel" became Legna, Breaker of Genes, Elsa became Asle, breaker of Ice. Melody became Ydolem, Breaker of Oceans and Arthur became Ruhtra, Breaker of Thrones) further empowered by the Miraculous from Miraculous Ladybug that Bega stole, he then used the Hawkmoth Akumatization to control his Breakers... All except Max, who turns out, joined willingly after finding out his whole world and life had been a prison.
*Eda Clawthorne is a galactic Kleptomaniac, going to other worlds, taking what she wants. The party had to fight her a number of times. She's also the reason that the Calamity Box ended up in that Charity Shop that Anne and friends found it. (She traded it with the lady there for a Dreamcast which had a copy of Chu-Chu Rocket and Sonic Shuffle.)
*The Unversed are actually a naturally occuring part of the universe. When someone with a particularly strong heart has their heart broken (Figuratively and literally) the little buggers pour out and do their masters bidding... Problem is that a broken, strong heart is a dinner-bell to the Heartless. Meaning that it's only a matter of time before the host and their world are consumed. This happened a number of times. Edgar from Aristocats, Jenny from Oliver & Company (Including a graphic scene where, just after her heart breaks, she's grabbed by Sykes, they see him drive 50ft away before the car stops, shakes and rattles as the sounds of ungodly screams of terror and howlig are heard from within, before the car grows spider-legs, turns around and the gang see's a human and 2 dog skeletons in the windscreen. They ended up fixing her heart and taking her and Oliver to Neverland, while Fagin and the gang were relocated to 101 Dalmation Street world.)
*Dreameaters are also naturally occurring. When a World Heart is destroyed, all of the dreams from within it pour out into the universe. These become the Dreameaters. Spirits flock to Princess' of Heart to protect them whereas Nightmares mostly focus on killing Heartless and Nobodies.
*Herbie the Love Bug is actually a Keybarer who helps any other Keybarers in need of transport. The gang used him several times in chase sequences. His Key-weapon is a Rocket Launcher.
*You don't reform someone who has been split into a Nobody and a Heartless by killing both, that's just stupid. You have to get them back together and unlock both at the same time in the same place.
*The Tournament of the Gods in Hercules world turned out to be a plot by Am and Hades to gather the greatest warriors from the galaxy i one place to copy their powers for a Genome Army. Jango Fett serving as the base, with 99 being the test-batch. She then created a Bad Batch by copying powers from different participents. Hunter created from Locke's natural leadership abilities, Wrecker created using Hercules' strength, Tech created by stealing Cid's intelligence, Crosshair created from Robin Hood's unmatched archery skills and Echo created using NOS-4-A2's technologies. Unfortunately for Am, 99 saw what she was doing and sabotaged the Bad Batch, giving them their own independence. She killed him in revenge and the Bad Batch sided with Karre against her for this.
*Belos actually did escape into the multiverse, stealing one of the old player characters bodies and gathering up as much technology and magic as he could to try and destroy all magic in the universe. Including stealing the Sandersen Sisters book and the Core from Amphibia.
*Tadashi actually survived the explosion in Big Hero 6, being blasted out into the Space Between and being found by Maleficent, who agreed to spare his world if he worked for her. He created Dark Baymax and took on the persona of
Shiv Katall so nobody would know his shame.
*The party went 0-3 against Captain Hook (They NEVER actually defeated him. Just shitty luck on their part and me using a fan suppliment that rated him as "CR: 3" when he ABSOLUTELY was NOT CR: 3. Hell, they fought him at Level 8 and he still wrecked their shit. We joked that, like the games, the random Hook Difficulty Spike struck again.)
*At one point, the gang broke the universe and caused a tear in reality, revealing a whole other universe where
"The Other Guys Lived" This lead to some great moments. Including one of the party who'd lost their body in the course of tearing the hole between universes, meeting the Warner Siblings who gave him an
Artificial Nobody to house his heart in for a while*Bega and crew tried to mind control the Madrigal girls in order to marry them and take control of the Miracle. This is where we established the rule that "Music is the most powerful magic in the universe, completely incorruptible." As, despite being brainwashed into not remembering any of the men in their family existing, Mirabel still sings about them during her big "The Family Madrigal" routine.
*Because Kao-Cen-Dorach was in Hollow Bastion when the MSG went off, he was also split, but his Heartless and Nobody remained in-tact and actually lied in relative harmony. His heartless was Darth Maul and his Nobody was Bao-Dur.
*There was a long running joke where Yojimbo was
The Lock Ness Monster where the moment the gang gave him money, he just kept on showing up, never saying anything, but putting out his hand and the gang kept giving him money. He did show up at several points to save them because they kept giving him tree-fiddy.
*A considerable chunk of the game was spent referencing
Just A Pancake's "Kingdom Hearts In A Nutshell Lots of failed Insight checks followed by "Ok, i believe you"