Indeed, Wolverine and Sabertooth are considered brothers in the comics. However, their interactions are filled with rivalry and hostility, making their brotherhood a very strained one.
It's hard to say who is more powerful. Blade has his vampire - slaying skills and speed. But Wolverine has his adamantium claws and that incredible healing factor. In a straight - up fight, Wolverine could take a lot of hits from Blade and keep coming back. However, Blade might be able to use his knowledge of the undead and his specialized weapons to gain an advantage.
Well, Naruto is often a central figure as he is the main character in the Naruto series. In the context of the fanfiction with Sabertooth, Sting would also be a main character. He has his own set of powers and a distinct personality. Then there might be other characters like Kakashi from Naruto who could play important roles, and from Sabertooth, Minerva could be involved. They all contribute to the overall story, with their different skills and goals.
Some plots might focus on character development. For example, a Naruto character could be sent to train with Sabertooth and come back with a whole new set of skills and a changed personality. Or a Sabertooth member could go to the Naruto world and be influenced by their values. There could also be a plot about a forbidden love between a character from Naruto and one from Sabertooth, which would create a lot of drama and conflict.
In the 'Death of Wolverine Graphic Novel', apart from Wolverine himself, there were several key characters. One was Dr. Cornelius, who was involved in the events leading up to Wolverine's death. His actions and motives were central to the plot. Then there was the character of Mystique. She has always had her own agenda and her role in this story was to manipulate the situation to her advantage. Also, characters like Cyclops, although not as central as some others, still had their reactions and interactions related to Wolverine's death which were important in showing how the X - Men as a whole were affected by this major event.