The 4 Lords

There are two basic worlds, the Shinobi world and the Rogue world. the Rogue world is ruled by 4 SR-class Shinobi. These 4 lords are very powerful Shinobi that only yields to the Akatsuki sometimes. The only person they respect is the leader of the Akatsuki. The only shinobis that would really stand a chance would be first-class shinobi or higher. No shinobi can kill them quickly as these 4 lords almost equal the power of the sannin. Even though they are in alliance with each other, they do not trust each other. Any other questions ask the leader of the Akatsuki, Inushi

Update for the 4 Lords - There is a sea captain by the name of Raven. She has learned many different jutsus as she is a member of the Uchiha clan. She is one of the very few who can use the mangekyo sharingan. The four lords would never think about crossing her or Inushi as Inushi is leader of the Akatsuki and Raven is captain of a ship called Mistress of the Sea. Her crew contains at least 500 shinobi. They stay on an Island that is really hard to find if you do not know how to navigate the oceans