Well, obviously Naruto and Tifa are the most popular since they are the main focus of this fanfiction concept. Their unique personalities and abilities make them stand out. Naruto with his energetic and determined self, and Tifa with her tough yet caring nature.
Sakura from Naruto might also be a popular character in some Naruto x Tifa fanfictions. She could be a bit jealous of Tifa's relationship with Naruto at first, but then they could end up becoming friends. Her medical ninjutsu skills could be useful in some storylines where they are all facing dangerous situations.
One popular storyline could be a crossover adventure. Imagine Naruto finding himself in the world of Final Fantasy VII where he meets Tifa. They might team up to fight a common enemy that is threatening both their worlds. Maybe a new villain emerges that combines the dark magic from Naruto's world with the technological threats of Tifa's world.
The story could be about Naruto finding a new family in Tifa. Since Naruto grew up without his parents, Tifa could offer him the motherly love he always craved. He might learn about Tifa's past and her own struggles, and in return, he could share his experiences from the ninja world. This would create a deep bond between them, and Naruto could start to see Tifa's world as his own, protecting it with his ninja powers.
One interesting storyline could be Naruto finding himself in the Final Fantasy VII world and teaming up with Tifa to fight a common enemy. Maybe they use Naruto's ninja skills and Tifa's martial arts to take on a powerful foe threatening both their worlds.
Perhaps in a 'naruto x tifa lemon fanfiction', Tifa could be transported to the Naruto world. She might initially struggle to adapt to the ninja - based society. Naruto, being the friendly and helpful character he is, would assist her. As they spend time together, they start to understand each other's strengths and weaknesses, which could lead to a deeper connection. However, they also have to deal with the politics and power struggles in the Naruto world that might threaten their relationship.
Honestly, the idea of 'naruto x tifa lemon fanfiction' is a rather strange crossover. Naruto has its own unique world with ninjas and chakra, while Tifa is from a very different RPG world. While there may be some fan - created works that attempt this combination, it's likely that they are more of a novelty. You might have to search through various fanfiction websites and forums dedicated to both Naruto and Final Fantasy to find any, but don't expect it to be a common or mainstream type of fanfiction.
Since Naruto is a ninja from a world full of jutsu and Tifa is a strong - willed fighter from a more technological fantasy world, this fanfiction could be trying to blend their characteristics in an unexpected way. The 'oven' might be a metaphorical or literal device used to bring them together. For example, it could be a part of a scenario where they are forced to cooperate in a kitchen - related task (if it's a non - adult version). But again, it's difficult to know precisely without actually reading the fanfiction.
One popular theme could be adventure. Since Tifa is a strong character from a game world, fanfictions might explore her going on new adventures. Another theme could be friendship, perhaps showing her deepening her bonds with other characters. And of course, romance is also a common theme, exploring her relationships in a more in - depth and creative way.
Some fanfictions also focus on Tifa's backstory. They might explore her childhood, how she grew up and trained, and how those experiences shaped the person she became in the main story. This gives readers a deeper understanding of her character.
I'm not sure specifically which are the most popular ones. You could try searching on fanfiction websites like Archive of Our Own. They usually have a large collection of such stories and you can filter by popularity, ratings, etc.
Some themes include the transformation process. If Cloud becomes a vampire, the fanfiction might explore how he deals with the physical and emotional changes. It could be a very painful and confusing time for him. And of course, there's the theme of protection. Cloud, even as a vampire, would likely feel a strong need to protect Tifa from other vampires or threats in the vampire world. This theme can drive a lot of the action and plot in the fanfiction.