Overall, the Eyeshield 21 manga is excellent. The plot is full of excitement and surprises, and the character development is well-done. The sports action is depicted vividly, making it a thrilling read.
Fem Sena fanfiction often explores different aspects of the character. It could be about her relationships in the Eyeshield 21 world. Maybe she forms new friendships or rivalries that were not in the original story.
One idea could be exploring the backstories of the supporting characters in more depth. For example, what led Hiruma to become such a devious yet brilliant quarterback? Another could be a 'what if' scenario, like what if Sena never joined the Devil Bats. It could also be interesting to write a fanfiction about the future of the characters after the events of the series, perhaps their college football careers or how they use the skills they learned in other aspects of life.
A common theme is power - up. Just like in Naruto where characters gain new powers and abilities, in fanfictions combining with Eyeshield 21, football players might gain Naruto - like powers to improve their game. For example, they could use shadow clones to practice plays simultaneously.
In 'eyeshield 21 hiruma x mamori fanfic', their relationship is often complex. Hiruma is a very cunning and strategic character, while Mamori is more of a caring and responsible type. Their interactions can range from Hiruma's teasing and involving Mamori in his wild football plans to Mamori trying to keep Hiruma in check. It's this contrast that makes their relationship in fanfics so interesting to explore.
First, re - watch or re - read the original series to get a fresh feel for the characters and the story. Then, pick a concept, like I mentioned before, it could be a character's backstory or a 'what if' situation. After that, just start writing. Don't worry too much about making it perfect at the start.
One great fanfiction is 'The Unlikely Bond'. It beautifully explores the dynamic between Hiruma and Sena. The author does an amazing job of showing Hiruma's protective side towards Sena, which is a side not often shown in the original work. It's full of heartwarming moments and also some intense football action that makes it a great read for any Eyeshield 21 fan.
One idea could be a crossover with 'Haikyuu!!'. The characters from Eyeshield 21 could visit Karasuno's volleyball team and have a friendly sports competition that combines football and volleyball skills. Another could be a crossover with 'Naruto'. Maybe the Eyeshield 21 team gets transported to the Ninja world and has to use their football skills to escape from enemies. A third idea is a crossover with 'One Piece', where the football players join the Straw Hat crew on an adventure and use their athleticism to help out in battles on the Grand Line.
Often, Naruto and Sena from Eyeshield 21 are a popular pairing. Their different personalities, with Naruto's boldness and Sena's initial shyness, can create an interesting dynamic. They could learn from each other's determination and growth throughout their respective stories.
In some Naruto x Eyeshield 21 fanfiction, there could be a plot where the ninjas compete against the Eyeshield 21 players in a modified version of football. The ninjas would use their unique abilities like shadow clones or chakra control to gain an edge. It would be a fun mix of two different worlds. Or perhaps there's a story where a character from Naruto has a doppelganger in the Eyeshield 21 universe and they switch places, leading to all sorts of comical and challenging situations as they try to adapt to the new environment.