In some fanfics, Naruto absorbs the bloodline through a special jutsu. For example, he might find an ancient scroll that contains a jutsu allowing him to transfer and absorb the genetic traits related to a bloodline.
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.
It could also be part of a strategic move. By hiding his bloodline, he can surprise his opponents in battle. They would underestimate him based on not knowing about his true powers, and then he could turn the tables on them when the time is right. This gives him an edge in combat situations.
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.
Well, the Saiyan bloodline can change Naruto's character in multiple ways. Firstly, his sense of pride gets a boost. Saiyans are proud warriors, and Naruto starts to take more pride in his abilities. He may become more confident, not just in his ninja skills but also in his physical strength. Secondly, his temper could be shorter. Saiyans are known for their short tempers when provoked, and Naruto might show this trait more often. He could get angry more easily, especially if someone challenges his newfound Saiyan - related powers. However, he still has his ninja values deep down, so there's an internal struggle between his Saiyan - influenced self and his original ninja self.
In some fanfictions, Naruto might obtain the bloodline through a magical or spiritual connection with the Fem Kyuubi. Maybe during a moment of extreme danger or a special ritual where the power of the Fem Kyuubi is transferred to him, allowing him to gain a new bloodline.
One unique ability could be the power to manipulate bones at a molecular level. This would allow the character to reshape their bones into various forms, like sharp weapons or protective shields. Another ability might be the capacity to sense vibrations through the bones, giving them an edge in combat by detecting enemy movements even through solid objects.
There could be a character named Kuro, who has the skeleton bloodline and uses it to create bone wings to fly. Another is Yuki, who can freeze her bones and use them as ice - like weapons. Then there's Hikaru, who has the ability to make his bones glow in the dark, which he uses to blind his enemies.
The Wolverine bloodline's healing factor would be a game - changer. In the Naruto world, where battles can be extremely brutal, this ability would make a ninja almost unkillable. They could take on much stronger opponents without the fear of dying easily.