It could be that the assassin was initially a victim of some dark wizard's experiment. Harry, being the hero he is, feels responsible for the child and decides to raise him. In the process of raising, he unknowingly nurtures the assassin-like qualities in the child because of the unique circumstances and challenges they face together.
One challenge could be controlling the assassin's violent tendencies. Since the person is being groomed to be an assassin, it's likely they have a natural inclination towards violence, and Harry has to find a way to temper that while also teaching self - defense.
Well, his story would be extremely different. For one, he'd be trained in stealth and combat skills from a young age instead of learning magic at Hogwarts in the traditional way. He might not have the same group of friends as in the original story. Instead of having Ron and Hermione as his closest allies, he could be more solitary or have assassin - type comrades. His view of good and evil would also be more blurred as an assassin, perhaps seeing the world in terms of targets and those who hire him rather than the clear - cut good vs. evil of the wizarding world. And his relationship with Voldemort would be more of a hit - or - miss rather than the epic battle of good against evil.
Yes, there are likely to be such fanfictions. The 'Harry Potter' universe has a vast and creative fanfiction community. Some fans might come up with the idea of Harry Potter being a Muggle assassin as a way to explore different storylines and character developments outside of the original canon. It could involve Harry using his magical skills in a Muggle - centered, assassin - like role, perhaps to protect Muggles from dark magic threats in a more covert way.
Maybe it's a character who has a hidden identity. It could be someone who was thought to be dead but actually survived and is now seeking revenge. This person could have a grudge against Moody for something that happened in the past. Or it could be a new character created specifically for the fanfic, a dark wizard from a far - off land who has been hired to kill Moody.
Perhaps an international wizard who has been trained in both magic and martial arts in some far - flung magical school. This wizard - assassin has his own code of ethics and when he meets Harry, he decides to take him under his wing, believing that Harry can be a force for good in a different way than the traditional Hogwarts - trained wizards.
Often, she'd be depicted with enhanced physical and magical abilities. Since she's an assassin, she'd need to be extremely quick and precise. Her knowledge of potions might be used to create poisons or antidotes for her missions. And her ability to apparate would be crucial for getting in and out of dangerous situations quickly.
In this fanfiction, the settings blend by creating new landscapes. The magical architecture of Hogwarts might be combined with the ancient structures of Assassin's Creed cities. For instance, the towers and battlements of Hogwarts could be used as vantage points for Assassins. The Ministry of Magic building could be located near an Assassin's Creed stronghold. Also, the dark and mysterious places in both settings, like the catacombs in Assassin's Creed and the Chamber of Secrets in Harry Potter, could be connected, perhaps leading to a new and dangerous underworld.
It could be a rogue Death Eater who has mastered a new form of invisibility spell. This Death Eater might be seeking revenge on those who opposed Voldemort.
Well, it depends on the specific fanfic. Some fanfics might portray Harry as an assassin, while others could have him in completely different roles. There are countless interpretations in the fanfic world, so we can't say for sure without looking at the particular story in question.
No. Harry Potter is mainly known for its own magical world and themes of friendship, good vs. evil, etc. Turning Harry Potter into an assassin fanfiction goes against the original spirit of the series and is likely not popular among the mainstream Harry Potter fans.