It's not appropriate at all. Fanfiction should be a creative and positive exploration of the original work, not a medium for inappropriate content. There are so many other positive ways to engage with the 'Leon: The Professional' concept without delving into sexual fanfiction.
Hunnigan could be a great addition. She could provide Leon with information and support from the outside, and her presence could add some tension as she might be suspicious of Ada's motives. Another good character is Wesker. His past connection to Ada could create more drama and conflict in the story. He could be a shadowy figure trying to manipulate the situation between Leon and Ada.
One great Merlin Sir Leon fanfiction is 'The Bond of Knights'. It beautifully explores their relationship within the context of Camelot's challenges. It shows how their loyalty to each other and to Arthur deepens over time.
I'm not sure specifically as 'leon the professional sex fanfiction' involves inappropriate content. We should focus on positive and appropriate literary works like the original 'Leon: The Professional' which is about the relationship between a young girl and a professional assassin in a non - sexual context.
One popular Leon and Jill fanfiction might be those that explore their partnership in a post - apocalyptic world. They could be facing new threats together and their relationship develops as they rely on each other for survival.
One great 'Female Merlin and Leon' fanfiction is 'The Enchanted Bond'. It beautifully portrays their relationship in a magical world filled with adventure. The author does an excellent job of developing their characters in a way that stays true to the original spirit of the Merlin series while adding a fresh twist with Merlin being female.
Well, there are several interesting Ada and Leon fanfictions. For example, 'The Encounter in the Shadows' is a fanfic that explores their first meeting from a different perspective. It shows how their initial distrust slowly turns into a begrudging respect. 'Ada and Leon: A New Alliance' is also good. It's set in a world where they have to team up against a new, powerful enemy and in the process, their relationship evolves in unexpected ways. Then there's 'The Lost Chapters of Ada and Leon' which fills in the gaps of their story that the official games might have left out.
Adventure is also a big theme. For example, they might go on quests together, and the fanfiction will detail their journey, the challenges they face, and how they overcome them using their respective skills - Merlin's magic and Leon's combat abilities. There are also fanfictions that explore the theme of trust, especially considering Merlin has to keep his magic a secret.
Survival is also a big theme. Given that they are usually set in a dangerous, post - apocalyptic world, they have to rely on each other to survive. This theme helps to build their relationship as they face threats from zombies or other villains.
A common theme is teamwork. Since both Leon and Jill are strong, capable characters from the Resident Evil series, many fanfictions have them joining forces to take on a powerful enemy. For example, they might work together to stop a new bioterrorist attack.