"One Piece" refers to the great treasure that Roger the Great Pirate asked people to look for before he died.

Gol D. Roger, a man with wealth, fame, power and everything in the world, said a word before his execution and death, which made people all over the world flock to the sea. "Want my treasure? Look for it in the sea if you want. I put it all there. " , the world began to meet the arrival of the "big pirate era". In "An Age of Pirates", in order to find the big secret treasure "One Piece" left by the legendary One Piece, countless pirates raised flags and fought.