One challenge is getting the power systems right. Naruto has chakra - based powers like ninjutsu and DxD has magic and devil powers. Combining them in a believable way can be difficult.
One challenge is creating a believable crossover world. Since Naruto, Espada, and Highschool DxD all have very different settings and power systems, it's difficult to make them blend seamlessly. For example, Naruto's chakra system and the DxD's magic system need to be reconciled in a way that makes sense.
Another issue is the power balance. The power levels in DxD and Naruto are quite different. In Naruto, it's mainly about chakra and ninja techniques, while in DxD, there are all kinds of devil powers. Writers need to find a way to make the interactions between characters with such different power sources believable.
A major challenge is the fan bases. Both Naruto and High School DxD have large and passionate fan bases with different expectations. Some Naruto fans might not like the more risqué elements of High School DxD being incorporated into a fanfiction, and vice versa. Writers need to be careful not to alienate either fan base. Additionally, the lore of both series is extensive. Trying to incorporate relevant parts of both lores without overloading the story or getting things wrong is quite a task.
One challenge is the difference in power systems. Naruto's chakra - based powers and DxD's devil powers are very distinct. Writers need to find a way to balance them. Another is the cultural and world - building differences. Naruto has a more Asian - inspired world with ninja clans, while DxD has a more Western - inspired demon - focused world.
One challenge is the difference in power scales. Naruto characters can have extremely powerful jutsus like the Rasengan or Sage Mode, while High School DxD characters have their own unique powers like Sacred Gears. Balancing these power levels in a fanfiction can be tricky.
The settings are also very different. Naruto is a more traditional Japanese - inspired ninja world, while Highschool DxD is set in a modern - day high school with a lot of supernatural elements. Writers need to blend these settings well so that the story doesn't feel disjointed. For example, if a character from Naruto enters the Highschool DxD world, how do they react to modern technology and the different social norms?
One challenge is integrating the two very different universes. The Transformers universe is based on science - fiction concepts like advanced robotics and intergalactic travel, while Highschool DxD is more about the supernatural and a school - based setting. So, making the two fit together seamlessly can be difficult.
The different character personalities pose a problem. Naruto is generally optimistic and energetic, while Sansa has been through a lot of trauma and is more complex. Combining them in a 'lemon' context while staying true to their characters is no easy feat. Also, the 'lemon' aspect means dealing with mature themes, which requires a certain level of writing skill to handle tastefully without making it seem out of place.
One challenge is the different universes they come from. Naruto has a ninja - based world with chakra, while Tohka is from a world with spirits and different power systems. Merging these two worlds in a believable way is difficult. Also, if it's a 'lemon' fanfiction, it might cross the line of appropriate content, which is a big no - no in many fan - fiction communities.
Well, writing 'female Naruto x futanari' fanfiction has several challenges. Firstly, in terms of the Naruto canon, Naruto has a specific backstory, goals, and relationships. Changing Naruto's gender and then creating a relationship with a futanari character means re - imagining a lot of these elements. Secondly, the concept itself is not very common in the Naruto fanfiction community, so finding an audience that will appreciate this kind of work can be hard. The writer also has to be careful with the way they handle the sexual or romantic aspects, if any, as it can easily cross the line into inappropriate territory. And finally, they need to make the story engaging and not just rely on the novelty of the pairing.