The Professor would be a bit worried at first. He's always seen the Powerpuff Girls as his little girls, and the idea of them in a relationship is strange to him. But if he sees that Lil Arturo is a good person, he would slowly come around. The Mayor would probably be really excited and try to throw a parade in their honor. The villains, on the other hand, might see this as a weakness in the Powerpuff Girls. Mojo Jojo could try to use Lil Arturo to get to the girls, thinking that their love for him would make them vulnerable.
Well, the plot could involve Lil Arturo being a new character in Townsville. He might be an artist who sees the Powerpuff Girls saving the day one day. Blossom catches his eye with her leadership skills. He starts leaving little artworks for her as a sign of his admiration. And Blossom, being a bit curious, starts to seek out who this mystery artist is. Eventually, they meet and start a very innocent and sweet romance, like going on picnics in the park and him painting pictures of her flying.
Bubbles would be a great character to pair with Lil Arturo. Her kind and friendly nature could contrast with Lil Arturo's more mischievous side, creating an interesting dynamic. They could have adventures together where Bubbles' flight ability comes in handy. Another good option is Professor Utonium. He could be a mentor figure to Lil Arturo, guiding him in his scientific experiments or helping him understand the world of superpowers. Also, the Rowdyruff Boys could be paired with Lil Arturo. They are all a bit on the wild side, and their combined chaos could lead to some really exciting and action - packed stories.
One common theme is friendship. Lil Arturo often forms a bond with the Powerpuff Girls, and they support each other through various situations.
There could be a 'powerpuff girls lil arturo fanfic' that focuses on the friendship between Lil Arturo and the Powerpuff Girls. In this story, he helps them understand the local neighborhood better, adding a different perspective to their crime - fighting adventures. He might introduce them to his friends and they all work together to make the town a better place.
A plot idea could be that Lil Arturo discovers a new type of energy source that is both beneficial and dangerous. The Powerpuff Girls initially suspect him of using it for evil, but as they investigate, they find out he just wants to use it to help the city. So they all team up to harness the energy in a safe way. Another could be Lil Arturo befriending a new character who has a hidden agenda against the Powerpuff Girls. He has to decide between his new friendship and doing what's right when he finds out the truth. Also, Lil Arturo could be shrunk down to a tiny size and has to rely on the Powerpuff Girls to help him get back to normal, and in the process, he learns about their true powers and personalities.
They could also interact in a more everyday - life - like way. Imagine the Gorillaz inviting the Powerpuff Girls to their home. Bubbles would be excited to see all the cool musical instruments. Blossom would be interested in their creative process. Buttercup might get into a friendly wrestling match with Russel. 2D could draw pictures of the Powerpuff Girls, and Murdoc would try to convince them to be part of his next big scheme. Noodle could cook a meal for everyone, and they would all share stories about their different worlds.
Pansy Parkinson would likely have a very different reaction. She might be more excited about the change, seeing it as an opportunity to be even more fashionable and to stand out in a different way. She could use her new appearance to gain more popularity among the students or to make a stronger statement within the Slytherin house.
It could be various fans. Some write it out of pure love for the show, while others might be inspired by certain elements to create their own stories.
Well, obviously the main characters would be the Powerpuff Girls - Blossom, Bubbles, and Buttercup. And Sonic the Hedgehog would also be a central character. There could also be other characters from both universes like Professor Utonium from the Powerpuff Girls side and Tails or Knuckles from Sonic's side depending on the direction of the fanfic.
If Dib from Invader Zim were to meet the Powerpuff Girls, he'd be excited to find others who fight against the 'weird' and 'evil' forces. He'd probably try to convince them to help him expose Zim. The Powerpuff Girls might be hesitant at first, but if Dib shows them enough evidence of Zim's evil plans, they could team up.