A crossover with a fantasy world where Gai has to adapt to magic. Maybe he could learn magic spells and combine them with his sword skills. This would open up new storylines and character developments.
First, decide on the other universe or story you want to crossover with. Then, think about how Gai would fit into that world. For example, if it's a superhero universe, what kind of superhero would Gai be? After that, start with a simple plot idea like Gai arriving in the new world and facing an initial challenge.
I'm not familiar with this specific 'sword gai novel', so I can't say for sure. It could be a fantasy or adventure genre considering the word'sword' is often associated with such genres.
There's not enough information to determine exactly who Gai is. It could be a fan, a self - appointed protector within the fanfiction community, or perhaps someone with a personal connection to the Sakura concept in the fanfiction.
Maybe it's an existing minor character from the Harry Potter universe who is given a new identity and role as 'gai'. For example, a little - known wizard who has been living in seclusion but has some extraordinary abilities and decides to take Harry under his wing.
I'm not entirely sure about a specific fanfiction with this crossover, but it could be really interesting. Maybe in this crossover, Ruby's skills as an Archer could be combined with the power of the Sword of Remnant in a unique way. For example, she could use her archery skills to enhance the sword's attacks, or the sword could give her arrows some special powers.
Lee would probably be Naruto's closest ally. They both have a strong will and are not afraid to face challenges head - on. They could bond over their mutual desire to become stronger and prove themselves. Lee's enthusiasm for taijutsu might inspire Naruto to improve his own physical combat skills, and Naruto could in turn teach Lee some of his unorthodox ninja techniques.
There may be some fanfictions out there that involve Gai and Kakashi, but the 'lemon' aspect might lead to inappropriate or unethical content. It's better to focus on fanfictions that build on their canonical relationship. For example, stories about their training together, how they support each other during difficult times in the shinobi world, or their humorous interactions. These types of fanfictions are more in line with the spirit of the Naruto series.
One possible fanfiction could be about Gai teaching Naruto the power of his 'eyebrow' spirit. Naruto, always eager to learn new ways to become stronger, might initially be confused but then start to understand the significance of Gai's expressive eyebrows in his own unique way of combat. For example, Gai could show Naruto how his confident eyebrow raises can intimidate opponents, and Naruto could incorporate that into his own fighting style, like using it to psyche out enemies before launching a Rasengan.