The Underworld is the whole system of connections, smuggling, and shady dealings which eludes the World Government's control. It is mainly set in the New World. The Underworld is made of most of the criminal organizations from all over the world. Influential people such as Yonko, Shichibukai, World Nobles or Supernovas might be involved in it, as it allows for a lot of slave trading, weapons smuggling and goods dealing. The Underworld also possesses a lot of mercenaries and hitmen for hire. Most of its activity takes place in the New World, the only sea not under the direct dominance of the World Government, although its also present in other seas. The most influential man in the Underworld was previously said to be Donquixote Doflamingo under the alias Joker. Other important figures are the Emperors of the Underworld, who are often the leaders in their specific activities.



Du Feld, known as the "God of Fortune", is the "Black Market King" (闇金王 Yamikin-Ō?, Viz: "Loan Shark King"). He is a member of the Du Feld Conglomerate and an emperor of the Underworld. Du Feld is a rotund man with large ears, nose, and lips, and a scar between his eyes. His hair is arranged in cornrows, alternating between light and dark, and he wears a small pair of glasses and smokes a cigar. He wears a dark suit with a rose attached to his left breast, as well as a fur coat.D u Feld appears to be gracious and easily impressed by other people's abilities. However, this does not extend to everyone, as he rudely wondered why Drug Peclo was invited to Big Mom's tea party along with him, causing Stussy to call him small-minded. As an emperor of the Underworld, Du Feld has strong degree of power within it. His importance is recognized by the Yonko Big Mom, who has invited him to her tea parties.

Stussy is the "Queen of the Entertainment District" (歓楽街の女王 Kanrakugai no Joō?, Viz: "Queen of the Pleasure District") and one of the emperors of the Underworld. Stussy is a young woman with shoulder-length curly hair. She wears a light dress with darker diamond patterns on the bottom, a small cape, a sunhat with a flower on it, and high heels. She carries a purse with her. Unlike her occasionally more hostile fellow emperors, Stussy appears to be polite and disapproves of insults being thrown around. As one of the emperors of the Underworld, Stussy has some degree of power over it, and she is important enough to be invited to the Yonko Big Mom's tea parties.

Drug Peclo is the "Major Undertaker" (大手葬儀屋 Ōte Sōgi-ya?) and an emperor of the Underworld. Peclo is a large man with very puffy light hair resembling a lion's mane, who wears a metallic mask over the top of his face that has star markings over the eye holes. He also wears a light jacket with four pockets on the front, pants with the same pockets, a dark tie, and a belt. Peclo is not above insulting his fellow Underworld emperors, as shown when he retaliated against Du Feld insulting him. Like many people, he has a unique laugh: "Gugigigugi". As an emperor of the Underworld, Drug Peclo has a strong degree of power within it. His importance is recognized by the Yonko Big Mom, who has invited him to her tea parties. Peclo carries a scythe, and is shown to carry it over his shoulder. 

"Big News" Morgans is the president of the World Economic Journal and one of the emperors of the Underworld. Morgans is a very tall humanoid bird with small eyes and a large beak. His body is covered in feathers, and he has a large tail and wings that resemble human arms. He wears a top hat with a large striped feather in it, a light button-down shirt with a bow on the top, checkered pants, and a dark cape. Morgans seems to be excited by major events, looking forward to reporting them as news to the world. Morgans is in charge of the World Economic Journal, giving him control over the newspaper and the information it gives to people. Furthermore, as a boss of the Underworld, Morgans has some degree of power within it. His importance is recognized by the Yonko Big Mom, who invited him to a tea party. He also has deep bonds with the Germa, and his newspaper incidentally publishes a popular comic strip that features their army as its main antagonists.

Giberson, known as "The Concealer", is a veteran warehouseman and one of the emperors of the Underworld. Giberson is an older man whose back is slightly hunched. He has a big white mustache and wears a tall striped hat on his head; no hair can be seen on the top of his head. He wears a striped suit and pants. Giberson appears to be a heavy drinker, as he has always been seen with a bottle in hand, and often acts jovially drunk. As an emperor of the Underworld, Giberson possesses some amount of power within it. He is important enough to be invited to the Yonko Big Mom's tea parties.
  
"Deep Ocean Current" Umit is a shipping magnate and one of the emperors of the Underworld. Umit is an older man with bags and age spots under his eyes. He has long hair, a beard, and curled mustache, and he wears a large bicorne with anchor on the front and three feathers sticking out of the left side. He wears a dark coat over a ruffled shirt and wrinkled pants. Umit appears quite serious and angry, in contrast to the joy and amusement his fellow emperors show. As an emperor of the Underworld, Umit possesses some amount of power within it. He is important enough to be invited to the Yonko Big Mom's tea parties.