Poincaré Family

The Poincaré Family also known as the Poincarés, and the Bankers by the most informed people in the world, are a family of individuals noted for their outstanding Mathematical Prowess and for being the ones running the world economy.

History
The Poincaré family is a family that dates to at least 400 Years ago founded by the great mathematician Ludwig Poincaré. Ludwig amassed an immense amount of wealth due to his genius intellect and expert mathematical ability to build an immense trade empire, this eventually lead to him being known in his time as the world's Greatest Merchant. However Poincaré found himself sick at a very early age and with a still young child he decided to sell all of his trade property to the world Government so they would take in his son Wilhelm Poincaré and raise him as a noble.

Wilhelm grew up and eventually was shown to also be a mathematical prodigy, having established the economic principles by which the World Government rules by today and preventing the economy from collapsing by the existence of the World Nobles and their reckless spending Wilhelm was given the honorary title Earthly Dragon (地竜人) for the greatest of contributions to the World Government.

While it's an unknown fact by many, especially the World Government Wilhelm himself also played a grand part in the establishment of the underground trade services while formulating the economic principles of the World Government.

Because of their title the Poincaré are a group almost as powerful and influential as the celestial dragons but do not get their funding from the Heavenly Tribute nor have access to the full forces of the Navy and are utterly incapable of sending an admiral to deal with their foes. However because of the Pitch Black Contract the World Government has given exclusive rights to the economic control of the world to the Poincaré and a selective few other world government operatives.

While rare it's not unheard of for a Poincaré to marry a celestial dragon and the offspring is born bearing the title of World Noble, one such example is Saint Marianne the only living World Noble Poincaré.

Achievements
The Poincarés have achieved many mathematical breakthroughs over their long years of existence and while impressive none of them have shed much light into the technological progress of the One Piece world until the birth of Vegapunk who has built upon the theories left behind by the Poincarés over the years.

However the economic impact of the Poincaré family in the world is incomparable to that of any other entity as the family has for centuries been the ones running the economy of the world and are at the heart of the principles in which it runs by.

Pitch Black Contract
The Pitch Black Contract is a 400 year old contract signed between Wilhelm Poincaré, all World Noble families and Government officials at the time that states that all of the world's economy is to be run by the Poincaré and their descendents.

Additionally it's established in the contract that the Poincarés economic affairs outside of the global scale are to not be interfered or researched upon by the World Government as a whole.

Mathematical Devil Fruits
For yet unknown reasons the Poincarés in almost their entirety are possessing of a Math Devil Fruit in one way or another. Furthermore most math based devil fruits have found their way into the hands of the Poincaré almost as if by guided by fate.

Those in the world who possess mathematical power from devil fruit consumption and are not a Poincaré themselves are very few and far between and an almost unspoken rule is that they do not live very long after consuming them.

Trivia

 * The Poincaré family is named after Henri Poincaré's family name and is furthermore inspired by the real world Bernoulli Family a family which produced an uncanny number of proliffic mathematicians.