Well, without having read the actual 'naruto is the manslayer fanfiction', it's hard to say precisely. It could be that the author has created a scenario where Naruto is forced to become a killer of men. Maybe there's a new villain in the Naruto universe who has pushed Naruto to this extreme. Or it could be a what - if scenario where Naruto's values are completely flipped and he starts seeing killing as a necessary means to an end.
Probably not. It sounds like a rather extreme and unorthodox take on the Naruto concept, so it might not have a large following compared to more mainstream Naruto fanfictions.
The unique take on the RWBY universe. If it's a'manslayer' fanfic, perhaps it has a character with a really distinct role or power related to that concept. It could be interesting to see how that character interacts with the regular RWBY cast.
Well, Battousai is commonly characterized as a highly skilled and dangerous figure in fanfiction. His cold and sometimes ruthless nature is a big part of his allure. Kaoru, in contrast, is the character that represents warmth and compassion. She is attracted to Battousai despite his flaws. In many fanfictions, their relationship is a journey. It starts with misunderstandings and gradually develops into a deep and meaningful connection as they face various obstacles together, like battles against common enemies or dealing with the secrets from Battousai's past.
One interesting concept could be exploring different moralities. In a 'naruto manslayer' fanfic, the idea of taking lives might be examined in the context of the Naruto universe, where typically the characters strive for peace and coexistence.
The term 'Battousai' is often associated with the character Himura Kenshin from the anime and manga 'Rurouni Kenshin'. In the story, Kenshin was once known as Hitokiri Battousai, a feared assassin during the Bakumatsu period in Japan. He was a master swordsman who killed many in the name of the revolution. However, after the war ended, he vowed to never kill again and carried a reverse - bladed sword as a symbol of his new pacifist ways.
There's a fanfic called 'Battousai in a New World' where the character is thrown into a different setting. It's interesting as it shows how he adapts using his skills and unique personality. It delves deep into his character development in an unfamiliar environment.