Monkey King is also highly popular. His long and rich history in Chinese mythology gives a lot of material for fanfiction. Writers can explore his past adventures, his relationships with other mythological beings, and how he mentors MK.
One idea could be exploring MK's training in more detail. Show his struggles and how he overcomes them. For example, he might face a new and extremely powerful demon that forces him to master a new skill quickly.
One idea could be a crossover with other Lego themes like Ninjago. The Monkie Kid characters could team up with the Ninjago ninjas to fight a common enemy. For example, a powerful dark force that threatens both their worlds. They could combine their unique skills and powers, like Monkie Kid's staff skills and the ninjas' elemental powers.
One possible plot could be that the Monkie Kid characters accidentally end up in the Ninjago realm. They meet the Ninja and at first there are misunderstandings as they don't know each other's powers and motives. But then they realize they have a common enemy, like an ancient evil that threatens both their worlds. So they team up, with the Monkie Kid using his magic staff and the Ninja using their elemental powers to fight this great evil.
First, choose the other franchise or concept you want to cross over with. Then, think about how the characters from both will interact. For example, if it's a crossover with a superhero universe, consider how Monkie Kid's powers compare to the superheroes' and how they'd work together or against each other.
The characters would likely start off being cautious of each other. For example, the Ninja from Ninjago, who are used to their own ways of fighting and protecting their world, might be a bit wary of the Monkie Kid and his friends with their different powers. But as they face challenges together, like fighting a common enemy, they would start to respect each other's skills. The more talkative characters from both sides would probably be the ones to break the ice and start sharing stories about their respective worlds.
An excited kid listening to a story may react in various ways. For one, they might make excited noises like 'ooh' and 'aah' at interesting parts. They could also repeat some of the words or phrases from the story in an enthusiastic way. Sometimes, they might even act out some of the scenes they hear in the story, like if it's about a superhero, they might pretend to fly around the room. Their reactions are a sign of their enjoyment and active participation in the story - listening is not a passive activity for them.
Scott would probably be very protective. He'd feel responsible for taking care of Stiles and making sure he doesn't get into too much trouble. Lydia might be initially shocked but then use her intelligence to try and figure out how to reverse the situation. And Derek, well, he'd probably be a bit annoyed at first but would also end up being one of Stiles' protectors.
Akane would probably be shocked at first. She might have some mixed feelings since she had her own relationship with Ranma in the past. But ultimately, she would likely be supportive and help out when she could. Ukyo, on the other hand, might be a bit jealous at first, but seeing how happy Ranma is with his new family, she would come around and be friendly towards the kid.