One interesting concept could be the combination of Naruto's ninja abilities with the unique traits of the Predator bloodline. For example, the Predator's cloaking ability might be used in a stealth mission in the Naruto world in an unexpected way.
Often, Naruto himself can be a main character. He might be the one who either inherits or has some connection to the Predator bloodline, which then changes his abilities and his role in the story.
It depends. Naruto has his powerful jutsu like the Rasengan and the ability to use Kurama's chakra. But the Predator has advanced weaponry and is a skilled hunter. If Naruto could get in close quickly with his speed, he might be able to overpower the Predator. However, if the Predator can keep its distance and use its long - range weapons, it could be a tough fight for Naruto.
Perhaps Naruto's transformation into a Predator - like being changes his appearance. He might have some Predator - like physical features such as glowing eyes or enhanced strength. This could lead to his friends initially being scared or confused, but as they see him use these new powers for good, they come to accept him. In the story, he could also learn to control these powers, so they don't overtake his original ninja nature.
There are also fanfictions where a bloodline is created through some sort of experimental jutsu. For example, a bloodline that allows the user to transform into different elements at will. This would give the character an edge in combat as they could adapt to any situation by changing their form.
The plot could start with Naruto being mysteriously transported to the world of the Predator. He finds himself in a strange and dangerous environment. As he tries to figure out where he is, he is targeted by a Predator. Naruto then has to use his ninja skills, like his speed and agility, to avoid being hunted. He might also try to communicate with the local inhabitants, if there are any, to learn more about the Predator and how to defeat it.
One idea could be that a Predator ship crashes near Konoha. Naruto, being the curious and brave ninja he is, investigates. The Predator technology could be something that both intrigues and challenges the ninja world. Maybe Naruto has to learn new ways to fight the Predator's advanced weaponry while also trying to communicate with it in his own Naruto - like way.
One common theme is the transformation of Naruto or other characters into a 'predator' - like state. This can involve changes in physical abilities or mental outlooks. Another theme is the clash between the Naruto world's ninja values and the more primal, predatory instincts. For example, Naruto may struggle to balance his normal ninja code with new - found predatory urges.
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.
He might use some special jutsu or seals. For example, he could use a sealing technique to suppress the signs of his bloodline. This way, others wouldn't be able to detect it through normal means like sensing chakra.