One interesting fanfiction could be where Cell somehow ends up in the Naruto universe. Maybe he's a new type of enemy that the ninja have to face. It could bring a whole new level of danger as his powers are different from the normal jutsu - based attacks in Naruto.
Cell's regeneration ability could be given to a character in Naruto. For instance, if Sasuke had this power, it would make him even more formidable in battles. He could lose an arm and quickly regenerate it, just like Cell.
In the fanfiction, the cell could be a source of great power but also a curse. It slowly starts to take over Naruto's mind. He has to fight against its influence while also dealing with the Akatsuki who want to capture him and use the power of the cell for their own evil purposes. Naruto would have to rely on his friends and his inner strength to overcome both the threat of the Akatsuki and the cell's dark influence.
The main antagonist could be Orochimaru. He's always been interested in unique powers and the cell within Naruto would be something he'd want to study and use for his own immortality experiments.
It could be someone from Goku's past who has a vendetta against him and takes advantage of the chaos during the Cell Games. For instance, an old enemy who was thought to be defeated but managed to come back stronger and wants to finish Goku off while he's weakened from the fight with Cell.
Goku is often one of the most common characters Cell interacts with. Since Goku is the main protagonist, their interactions can range from intense battles to unexpected team - ups. Vegeta is also a popular choice. The rivalry between Vegeta and Cell can lead to some great story developments. And then there's Trunks. Given Trunks' time - traveling abilities and his own power, he can have some really interesting crossovers with Cell.
First, do some research on how white blood cells and red blood cells function in the body. This will help you create a more accurate and believable story. For example, you can use the fact that white blood cells are part of the immune system and red blood cells carry oxygen.
Maybe a plot where the white blood cell and red blood cell get lost in the body during some sort of chaos, like a malfunction in the circulatory system. They then have to find their way back while facing various challenges and learning more about each other.
The title '18 struggles in cell grip fanfiction' is rather mysterious. It could imply that there are 18 distinct types of turmoil or problems within a setting that has to do with being in a cell - like confinement. This could be in a science - fiction setting where a cell might be a containment unit for some sort of experiment, or in a more traditional sense like a prison cell. The 'fanfiction' part suggests it's a work created by a fan, building on an existing universe, but again, without reading it, we can only guess what those 18 struggles might be.
It's basically fan - made fiction that crosses over elements related to cells. It could involve things like genetic crossovers in a fictional sense, where the DNA or cell functions from one fictional cell - type are combined with another. Maybe in a story, a scientist discovers a way to merge the unique properties of a plant cell from one fictional world with an animal cell from another, creating all sorts of interesting scenarios and conflicts.