One underrated character to include could be Mr. Lancer. Imagine if the Control Freaks try to control the school through him. Danny would then have to deal with the situation without blowing his cover. Also, Valerie could be a great addition. She has her own vendetta against ghosts, but in this fanfiction, she might have to team up with Danny when she realizes the Control Freaks are a bigger threat to the town than the ghosts she usually hunts.
In addition to the main characters, you could include some of the minor ghosts. For example, Ember could be interesting. She has her own powers and personality, and her presence could add more chaos to the situation with the Control Freaks. Another option is Technus. His technological know - how could either be a help or a hindrance in the fight against the Control Freaks, depending on how you write it. And of course, the Ghost Writer could also be a unique addition, perhaps using his writing powers to expose the Control Freaks' plans.
Obviously, Danny Phantom himself is a must - he's the main character. Then, the Control Freaks are essential as they are the focus of this particular fanfiction. Tucker and Sam are also great to include as Danny's friends. They can provide support, different perspectives, and sometimes comedic relief. Jazz could also be added, maybe she gets caught up in the Control Freaks' schemes in a way that forces Danny to act to protect her.
You could write a fanfiction where the Control Freaks manage to gain control over Amity Park in a more extreme way than ever before. Danny has to figure out how to break their hold not just on the physical aspects of the town but also on the minds of the people. This could involve him having to face some of his own fears and insecurities as the Control Freaks use his loved ones against him.
Danny himself is a must - include. His powers and his dual identity would add a lot of interesting elements. Tucker and Sam are also great choices as they could be Danny's support system while dealing with baby - related situations. Jazz could be included as she often has a more mature and understanding perspective. And of course, Danny's parents, who might be clueless about what's really going on with the baby but still add a lot of humor.
Definitely Sam and Tucker. They are Danny's best friends in the Danny Phantom series. Including them in the fanfiction can add some humor and also show Danny's normal life side. They could also interact with Ophelia in interesting ways, like Sam being a bit jealous at first of Danny's closeness to Ophelia.
Cisco Ramon from the Flash's universe would be a great addition. His ability to create new gadgets and his sense of humor would fit well in a crossover. For Danny Phantom's side, Frostbite could be included. His knowledge of the Ghost Zone and his ice - based powers could be crucial in a story where they are facing a powerful enemy. Also, including the Reverse Flash as a villain would create a lot of tension and action in the fanfiction.
Obviously Danny and Rouge are the main ones. But Tucker could be a great addition. He could provide some tech - support or comic relief. And for Rouge's side, maybe Shadow could be included. Shadow could add an element of mystery and power to the story.
Sam is a great character to include. She often provides a different perspective to Danny and Tucker's adventures, and her environmentalist views can add an interesting dynamic, especially when dealing with ghosts that are related to nature or pollution.
Sam Manson would be an excellent addition. Her strong - willed and goth - like nature can add an interesting dynamic. From the Kamen Rider side, if we consider Kamen Rider W, Shotaro Hidari could be included. His detective skills combined with Danny's ghost - hunting abilities would make for some great mystery - solving scenes. And let's not forget Jazz Fenton, Danny's sister. She could provide some emotional support and also get involved in the action in her own way.
Tucker would be a great addition. He could provide some comic relief with his tech - savvy ways. He might also be able to upgrade their ghost - fighting gear. Sam is another good one. She could offer her unique perspective on things, especially when it comes to environmental and ethical issues. And of course, Vlad could be included as the antagonist. His devious plans and power - hungry nature always make for an interesting conflict.
Sam is also quite popular. Her goth - like personality and her strong - willed nature make her an interesting character. In fanfiction, she can be portrayed in different ways, like being even more involved in Danny's ghost - fighting activities.
Well, in this kind of fanfiction, Danny could be controlled by an ectoplasmic parasite. The parasite latches onto Danny and takes over his actions. His eyes might glow a different color to show he's not in control. His friends would first be confused, then realize something is amiss and start investigating.