In a lot of fanfictions, Danny himself often becomes the most powerful ghost. As he grows and learns to control his powers better, he can surpass many of the traditional powerful ghosts in the show. For example, in some fics, he gains the ability to absorb other ghosts' powers, making him extremely formidable.
It's really hard to say. Danny has some incredibly powerful ghost abilities like intangibility, flight, and his ghostly wail. But Ben has access to so many different alien forms, each with their own unique powers. However, if we consider the fact that Danny has a connection to the Ghost Zone which gives him an almost unlimited source of power in a way, he might be the most powerful. But then again, Ben in his Alien X form has near - omnipotent power. So it really depends on how you define 'powerful' in the context of this crossover.
There's also 'Phantom's Unlimited Potential'. This fanfiction delves into Danny's untapped powers. It shows how he discovers new ways to use his ghost powers, like being able to manipulate time on a small scale within the Ghost Zone. This gives him an edge over other powerful ghosts he encounters.
Obviously, Danny and Dan themselves are very popular. Danny as the main hero and Dan as his dark and complex counterpart are central to many stories. Jazz, Danny's sister, is also popular as she can provide a different perspective and often gets involved in Danny's ghost - fighting adventures in fanfiction.
The Box Ghost is quite popular in Danny Phantom fanfiction. He's often used as a comical relief character, but can also be made into a more menacing figure in some stories. Another popular one is Skulker. His hunting nature and advanced weaponry make him an interesting character to write about. He can be a formidable foe for Danny or even an unexpected ally in certain situations.
The Box Ghost could be really unexpected. He's usually so focused on his boxes that seeing him at a party would be a shock. He might bring his boxes as party favors or something, which would be really odd. He could keep trying to stack his boxes in the middle of the dance floor, much to the annoyance of the other guests.
The most interesting element is often the transformation itself. It can be really exciting to see how Danny changes in different ways, like his powers getting enhanced or his appearance taking on new and unexpected forms.
Well, Danny Phantom has the ability to phase through objects and fly at high speeds, which is really cool. Ben 10 can transform into so many different aliens, each with their own unique powers. And Kim Possible is super athletic and has all those useful gadgets. However, I think Ben 10 might be the most powerful in a crossover. His Omnitrix gives him access to a wide variety of powers that can be used in different situations. For example, if they were in a fight underwater, he could transform into an alien that is adapted to aquatic environments. But again, it's all about how the story is written and what challenges they face.
There could also be some new ghost characters that are introduced as part of Danny's new role. Maybe a powerful ghost who was once an enemy but now has to work with Danny as he's the king. Or a young ghost who looks up to Danny and becomes his sidekick of sorts in the Ghost Zone.
The main characters are Danny and the Ghost Girl. Danny, as the half - ghost, has his regular battles with ghosts and his school life to balance, and the Ghost Girl enters his world and shakes things up. She could be a friendly ghost trying to help Danny, or she could be a more mysterious figure with her own agenda. Additionally, antagonists from the Danny Phantom universe like Vlad Masters might also show up in some fanfictions related to the Ghost Girl, creating more conflict and drama in the story.
Sam and Tucker are really interesting characters to focus on. Sam's gothic personality and her strong beliefs can lead to some great storylines. Tucker's tech - savvy nature can be used in many ways, like developing new gadgets or helping Danny figure out some tech - related mysteries. And Jazz, Danny's sister, with her psychology knowledge could play a crucial role in understanding Danny's situation better in a fanfiction.