No. Writing sexual fanfiction about a character like Professor Layton is inappropriate. Professor Layton is a character from a family - friendly game series. Fanfiction should respect the nature and intended audience of the original work, and creating such adult - themed content goes against that respect.
One interesting concept could be alternate universes where the characters have different roles or abilities. For example, Layton might be a villain instead of a detective.
One major ethical issue is the disrespect to the original creators and the intended audience. The creators designed Professor Layton to be a character in a non - sexual context, and by creating sexual fanfiction, it shows a lack of respect for their vision. Also, it can make the fan community an uncomfortable place for those who don't want to be exposed to such adult - themed content.
First, you should have a good understanding of the original Professor Layton series. Know the characters, their personalities, and the overall tone of the story. For example, Layton is known for his gentlemanly and intelligent demeanor.
One common theme is growth. Luke's growth as a character, both in intelligence and in his relationship with Professor Layton. Another theme is mystery - after all, they are known for solving mysteries in the original games.
If it's a crossover with the Final Fantasy series, characters like Cloud Strife could be included. Cloud's brooding nature and combat skills would contrast with Professor Layton's calm and cerebral approach. Tifa Lockhart could also be part of it, providing her own brand of strength and determination.
A crossover with the Pokémon world could also be fascinating. Maybe Professor Layton and his companions find themselves in a Pokémon region. They could use their wits to solve the mystery of a rare Pokémon that has been causing trouble in the area. The Pokémon trainers would be impressed by Layton's intelligence and problem - solving skills.
It's likely a visual novel related to the Professor Layton series. It probably features the same charm, mystery - solving elements, and engaging characters as the main games in the series.