Known to be one of the Four Emperors of the Sea and an apprentice of the former Pirate King, Gol D. Roger, Shanks is a tremendously important character, especially in the Final Saga of One Piece. He is also the individual who set Luffy out on the path of becoming the Pirate King, and even entrusted his own trusty Straw Hat to him. Shanks is, in many ways, the trigger of everything that's going on in the world of One Piece, and that's attached a special importance to him.