Yonko

The Yonko are considered to be the worlds' most notorious pirate captains (by the World Government), but are neither allies nor enemies of one another, preferring to remain independent under most circumstances. These four individually reside within the second half of the Grand Line (known as the "New World"), exerting impressive influence/control over dozens of other pirate crews and self-governing islands. In the climactic Battle of Marineford, one of the Yonko met his end towards the climax of the Whitebeard War, his killer subsequently replaced him as a Yonko and another Yonko stopped the war.