Maybe the Akatsuki as a whole. They are a group of powerful and dangerous ninjas. The Black Knight's presence might disrupt their plans to collect all the tailed beasts. They would see him as an obstacle and try to eliminate him. For example, Pain might think the Black Knight is a threat to his vision of peace through pain and send his subordinates to fight him.
One interesting plot could be the Black Knight having a secret connection to an ancient shinobi clan in Naruto. Maybe they hold a power that can change the balance in the ninja world.
Yes, it could be. Naruto has a rich world with elements that can be related to knight - like heroism and there are some romantic sub - plots that might fit into the idea of a knight romance in a fanfiction sense.
In RWBY fanfiction, the 'Black Knight' could be a variety of original characters created by different authors. It might be a mysterious figure with a dark backstory, perhaps having some sort of vendetta against the main characters or being involved in a shadowy plot within the RWBY universe as envisioned by the fanfic writer.
One difference could be his origin. Lelouch has his own unique backstory that might not be exactly the same as the typical Black Knight in fanfiction. His royal heritage, for example, sets him apart as he has a different perspective due to his upbringing in the imperial family.
The knight bloodline could be integrated as a foreign power that was brought to the Naruto world long ago. Maybe a group of warriors from another dimension with the knight bloodline came and settled, and over time their bloodline got diluted but still resurfaces in certain individuals.
Yes, there might be. The Naruto fandom is quite large and diverse, and it's not uncommon for fans to create crossovers like this. You can try searching on fanfiction websites such as FanFiction.net or Archive of Our Own.
One idea could be that Naruto discovers an ancient relic that transforms into knight armor. This armor could enhance his abilities, like making his Rasengan even more powerful. It might also change his appearance, giving him a more chivalrous look. He could then use the armor's special features, such as enhanced speed or defense, in battles against powerful enemies.
Sure. Given the creativity of fanfiction authors, it's not at all surprising that there could be a story where Naruto is a Holy Knight. In fanfiction, the boundaries are limitless. Writers can give Naruto all the characteristics of a Holy Knight, like noble intentions, special powers related to the Holy Knight concept, and put him in various scenarios that would be very different from the original Naruto storyline.
One great fanfiction could be one that delves deeper into the backstory of the characters in Black Knight Sword. Maybe it focuses on the protagonist's journey before the events of the game, exploring his motives and the world he came from. It could add more layers to his personality and make his actions in the game more understandable.