Sam and Tucker would definitely be his top allies. They've been with Danny through his whole journey as a half - ghost, and they'd support him in his new role as the Master of Death. Sam could offer her unique perspective on the moral and ethical side of things, while Tucker could use his tech skills to help Danny understand any new powers or situations related to his new title.
One way is to focus on Danny's emotional journey. Show his initial shock and disbelief. For example, he might find it hard to accept that his parents, who were always so full of life in their ghost - hunting adventures, are suddenly gone. This could lead to him feeling isolated as he tries to deal with this loss on his own.
Isolation can also be a theme. Danny may feel alone on his death day, as it's a very personal and strange experience for him. His friends may not fully understand what he's going through, so he has to deal with his emotions by himself at times. Additionally, the theme of power growth can be present. His connection to the Ghost Zone might be stronger on his death day, leading to new abilities or challenges related to his powers.
One idea could be Danny exploring the full extent of his new 'Master of Death' powers. He might discover he can not only control ghosts but also has the ability to manipulate death itself in ways he never thought possible, like bringing back certain spirits for a short time to right a wrong.
In this fanfiction, it could be that Danny Phantom meets a Danny Phantom from a parallel fan - made story. At first, they don't trust each other. But as they learn more about each other's worlds, they realize that there are some common elements that are being threatened. It could be that a powerful ghost is trying to rewrite all the fanfic universes related to Danny Phantom. So, they must combine their strengths and knowledge to stop this from happening.
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.
There could be a fanfic where Danny and Ember accidentally swap powers. This leads to a series of comical and also dangerous situations. Danny has to figure out how to control Ember's power of influencing people through music while Ember struggles with Danny's more combat - oriented powers. It could be a story full of self - discovery for both of them.
Another possibility is that he's facing some emotional turmoil. Danny has a lot on his plate. He has to keep his identity a secret from his friends and family, deal with school, and fight ghosts. All this stress could be causing him to lose his appetite. He might be too worried or preoccupied to even think about food.
One possible story could be that Danny is facing a new and extremely powerful ghost. He needs help from his friends Tucker and Sam. Maybe they need to find a rare artifact to defeat this ghost. They could start by researching in the local library, looking through old ghost lore books. Tucker uses his tech skills to try and track down any leads on the artifact's location, while Sam uses her knowledge of the occult.
Obviously, the main character would be Danny Phantom himself, but in two different forms or versions. One would be the original Danny Phantom from the canon source, and the other would be a version created by the fanfiction. There might also be his friends like Sam and Tucker who could play important roles in helping the two Dannys understand each other and deal with any issues that arise from their meeting.