It could be Harry Potter himself. He already has many extraordinary qualities like his ability to resist the Killing Curse. In fanfiction, he could be further developed into an 'ultimate life form' by gaining more powers, such as the ability to fly without a broom or to instantly heal any wound.
In Harry Potter fanfiction, the 'ultimate life form' could be a being with combined magical abilities from different species. For example, having the strength of a giant, the intelligence of a ravenclaw wizard, and the shape - shifting ability of an animagus all in one. It might also possess immortality, which is a highly coveted trait in the wizarding world.
A common theme is power exploration. Since Sonic is the ultimate life form, many fanfictions focus on his powers, how he got them, and how he uses them. For example, some stories might show Sonic learning new ways to control his speed or strength.
Percy Jackson would likely still be a main character. He has such a central role in the original series that it's hard to imagine a fanfiction without him. Another might be Annabeth Chase, as she's Percy's close companion. There could also be new characters created specifically for this fanfiction, like a mysterious ultimate life form character who becomes Percy's ally or adversary.
Fanfiction often takes the existing elements of the Harry Potter series and twists them in new and interesting ways. The idea of a 'demon form' could be used to expand on the lore of magical creatures in the series. For instance, it could be inspired by the existence of demons in the wizarding world's mythology. This form might have unique abilities like the power to control dark magic more effectively or to possess other beings, creating complex and engaging storylines in the fanfiction.
No. It's completely unacceptable. The Harry Potter series is aimed at a wide audience including children, and such a title goes against the moral and family - friendly nature of the original work.
One of the great stories could be those that explore alternate timelines. For example, a story where Voldemort won the first wizarding war. It gives a whole new perspective on the wizarding world. Another good type might be the ones that focus on the relationships between minor characters, like how Neville and Luna's friendship could develop further.
In Harry Potter fanfiction, the 'ultimate lifeform' can vary greatly depending on the author's imagination. It could be a being with extraordinary magical powers, perhaps one that combines the best traits of different magical creatures like the intelligence of a Ravenclaw and the strength of a giant. It might also be a new type of magical being that has powers beyond what is known in the original series, such as the ability to manipulate time and space in ways that not even the most powerful wizards in the books can do.
No, it's not that common. Most Harry Potter fanfictions tend to focus on relationships, new adventures, or alternative timelines. While there are creative interpretations, this 'fire form' concept is rather unique and not as frequently explored as other themes.
One interesting concept could be new powers for Percy. Maybe he has the ability to control not just water but also other elements related to the sea, like the ability to manipulate sea creatures' minds on a deeper level. Another concept might be a new form of the ultimate life form, perhaps a hybrid of different mythological creatures that combines the strength of a centaur, the speed of a harpy, and the wisdom of a sphinx.