"Created in secret by the United Nations, the Planetary Secret Service known as the CENTINELS is dedicated to defending the Earth from alien invasion. Amongst them 100 souls from 100 cities around the world have donned a powerful exoskeleton known as a CENTINEL-Suit, taking their place as secret combat agents known as Wonderful Ones. Once they have completed the most stringent training exercises, passed the toughest exam, been certified as physically fit, and approved as mentally sound, only the elite are chosen to enter as Earth's frontline defenses. From valour in battle to secret intelligence gathering, they undertake each mission with the utmost skill while concealing their identities as most classified. Their faces are forever masked. Their tombs are forever unknown. They are proud to go down in history as simply one in a hundred. They are the most wonderful defender of our world: The Wonderful 100."
―Narrator in Mission 000: Prologue

The CENTINELS Planetary Secret Service, created secretly by the United Nations, have branches all over the world, where carefully-selected individuals are trained into superheroes and dispatched on missions at a constant rate. Their goals are the annihilation of GEATHJERK forces remaining on Earth and the preservation of public safety. They are also always researching and developing new weapons to prepare for the next invasion while devising fresh defense strategies. Above all else, they focus their daily attention on the maintenance and improvement of the “CENTINEL-Suits” the Wonderful Ones wear.