Perhaps a mad scientist who wants to use the Dalmatians' unique genes for his own experiments. He kidnaps some of the puppies thinking he can create a super - dog race. The rest of the Dalmatians then have to rescue their captured family members and stop the scientist's evil plan. This villain would be more of a modern - day threat compared to Cruella de Vil.
A jealous show - dog breeder could be the new villain. He sees the Dalmatians getting all the attention and decides to plot against them. He tries to frame them for causing chaos at dog shows so that his own dogs can win all the prizes.
It could be a greedy land developer. He has plans to build a huge shopping mall on the land where the Dalmatians and their owners live. In order to clear the land, he decides to get rid of all the animals, especially the Dalmatians puppies which he sees as a nuisance. He sets traps and hires people to capture the puppies, making him a very menacing villain in the fanfiction.
A power - hungry magician in the city could be the villain. He sees the Dalmatians as having some sort of magical essence that he wants to harness for his own dark magic. Penny, with her love for the puppies, has to figure out how to stop the magician's evil plans. She might seek the help of other friendly animals in the city and use their unique abilities to combat the magician's magic.
A powerful wizard from a forgotten dimension could be the new villain. He sees Seabrook as a place full of unique energy that he can use to gain more power. He starts by creating chaos among the zombies, aliens, and humans, using his magic to turn them against each other.
A merman who was once in love with Ariel but turned bitter when she chose Eric. He could team up with some sea monsters and try to take Ariel back to the sea against her will, believing that she made the wrong choice in leaving the ocean for a human.
A group of mermaids from a far - off and isolated reef who are jealous of Ariel's family and their influence. They could plot to make Melody look bad in front of the underwater kingdom.
A tech - genius who was once a protégé of Tony Stark but turned against him out of jealousy. He creates his own army of robotic suits.
One possible plot could be that the Dalmatians discover a hidden talent among them, like the ability to communicate with other animals in a special way. They use this talent to save their neighborhood from a new threat, perhaps a developer who wants to destroy their park.
Sora would definitely be a main character. He's the protagonist in the Kingdom Hearts series, so it makes sense for him to be involved. The dalmatians themselves, especially Pongo and Perdita, could also be main characters. They could lead Sora through their world and help him understand their unique situation.
A corrupt politician could be the new villain. He uses his power and influence to cover up his illegal activities, like embezzling funds meant for the city's development. The Punisher would see through his lies and decide to take him down.
Perhaps a new character, like a genetically - engineered super - soldier gone wrong. This villain could have super strength and agility similar to Spider - Man, but with a more aggressive and unpredictable nature. He might see Spider - Man as a rival and be determined to prove that he is the superior one in the city.