Yes, he might be. In some fanfiction universes, the author could reimagine Harry as the first Sith. This could be a really interesting twist on the original character, creating a whole new story arc full of dark side powers and different moral challenges compared to the traditional Harry Potter story.
Well, it could be his backstory. Maybe in this fanfiction, Harry has a really tough life that leads him down the dark path of the Sith. For example, if he's constantly betrayed or faced with extreme hardships that make him lose faith in the good side, he might turn to the Sith ideology.
I don't know who specifically created 'harry the sith fanfic'. There are so many fanfic authors out there, and it could be someone from any corner of the internet who was inspired by both Harry Potter and Star Wars and decided to create this unique mash - up story.
A new character could be introduced as a Sith Lord. Maybe a wizard who has been studying dark and forbidden magic from other dimensions. He could have a red lightsaber - like wand and use powers that combine magic and Sith - like abilities. For example, he could use mind control not just on muggles but also on some weak - willed wizards.
Well, surely there would be a Sith Lord as a key character. They are central to the story given the title. This Sith Lord might be a powerful figure, with great knowledge of the dark side.
In Clone Wars fanfiction, Darth Maul stands out. He was initially thought to be dead after 'The Phantom Menace' but his return in Clone Wars brought a new level of danger. His thirst for revenge against Obi - Wan Kenobi and his attempts to regain his former power are common themes. Darth Sidious is also key. His devious plans to create chaos and gain ultimate power are often explored in fanfiction. He was using the Clone Wars as a means to an end, and fan writers love to play with the idea of what his true endgame was.
One memorable OC Sith could be Darth Zyra. She has a very distinct look with her purple - hued lightsaber and her elaborate black and red robes. Her power lies in her ability to manipulate the minds of her enemies, which she uses to great effect during battles in the Clone Wars.