Who are Maleficent's allies for the KH Divergence saga, and what is the story behind Pandemoniac Heartless Parade?
In my KH4, Maleficent has summoned all remnants of her old minions from Enchanted Dominion to assist her and the Heartless in their big magical science project with the relics of power from the ancient age and date from the Book of Prophecies (I'm not remotely kidding here, Maleficent goes full Arcane Hextech in this story!). In addition, she still has Pete and the Gullwings (Yuna, Rikku, and Paine) around, and Pete's called up the Beagle Boys to help too.
After KH4, however, Maleficent has been rendered powerless and with only two flunkies to carry out her plans for her - Pete, and the newly introduced Mortimer Mouse, a Duke from Disney Town who always wanted the king's throne and a Keyblade but could never have either, so he turned traitor back in the Disney Town/Castle segment of KH4. From the powers of darkness, Mortimer forged a faux-Keyblade that can slay Demi-Deterged and freeze hearts in place, but cannot actually unlock anything or set any hearts free. The duo of Pete and Mortimer would be set up in The Missing Links, but they don't get particularly active as a menace to the worlds until KH5.
Pandemoniac Heartless Parade? Oh, that is a fun one. The idea for that spinoff would be that it's a reality where Maleficent won in KH4 rather than get defeated and depowered. Her plan to submerge the existing World in darkness while she rules and dictates the course for the newly recreated "Ye Olde World" succeeded, so now she schemes to gain access to the real Kingdom Hearts via the false one that was a built-in thing for this Olde World. Said Olde World now sits atop the ruins of the previous World (like Piltover and Zaun, more Arcane shit there!) and rather than be split into different "worlds", it splits off into different "sectors", each ruled over by a Disney Villain who command their own forces. Within this setup, you create an OC to serve Maleficent and work alongside Pete and Mortimer (and other allies like the Gullwings and the Beagle Boys) in keeping things in check. The "story" comes as an Excuse Plot to intermingle with the Disney Villains and various enemies: all this World's Heartless, out of nowhere, start turning on each other and creating feuds between different classes of enemy and different villains who command them. Like there's OG Darkling Heartless VS Emblem Heartless, Colorful Heartless VS Dark Heartless, Humanoid Heartless VS Beastial Heartless, Organic Heartless VS Manufactured Thing Heartless, Heartless VS Unversed VS Nobodies VS Nightmares VS Demi-Deterged, etc. Obviously this creates a panic from Pete and Mortimer as they fear Maleficent's authority will be undermined this way, and SPOILERS: it turns out that's the whole idea, as Hades is behind all this and has been out to usurp Maleficent's rule from the start, and he's conspired with newcomer villain Cruella De VIl to put this scheme in motion. It's on your character to unravel the conspiracy and stop it so that...Maleficent can stay in power and ultimately unlock the way to Kingdom Hearts. You are playing as a baddie!
The villains that'd be featured aside from Maleficent and co.:
Madame Mim (villainous counterpart to Merlin)
Cruella De Vil
Hades, Pain & Panic, and the Titans
Ursula, Flotsam & Jetsam
Oogie Boogie, Lock, Shock, & Barrel
Captain Hook & Mr. Smee
Jafar
Shan Yu
Scar & the Hyenas
Gaston & LeFou
Dr. Hamsterveil, Jumba Jookiba, Captain Gantu & Reuben
John Worhington Foulfellow & Gideon
Dr. Facilier
Mother Gothel
Prince Hans of the Southern Isles
Prince John, Sir Hiss, and the Sheriff of Nottingham
Yzma & Kronk
King Candy/Turbo
and Dr. Heinz Doofenshmirtz
'Twould be so much fun, I so wish it was real!