Four Emperors (One Piece)
The Four Emperors (四皇, Yonkō) of the Sea are four fictional powerful pirates considered great powers in Eiichiro Oda's One Piece series. In the second half of the Grand Line known as the New World, the Four Emperors rule over separate empires consisting of several islands.
Source: Wikipedia — Four Emperors (One Piece) (CC BY-SA 4.0)