Doctor Reyga was a male Ferengi scientist who lived during the mid-24th century. He had the distinction of not only being one of a very few Ferengi scientists, but also of inventing the metaphasic shield.
In the late 2360s, Doctor Reyga invented the metaphasic shield, a type of shielding capable of protecting a vessel inside the corona of a sun. Reyga had to overcome a number of cultural prejudices to convince other scientists to listen to his ideas, eventually presenting his theory at the Altine Conference in 2369.
Dr. Beverly Crusher saw much promise in his concept and, later that year, invited Reyga along with many other scientists in the field of subspace morphology to the USS Enterprise-D to see a demonstration of the shielding in action. Only four scientists accepted Crusher's invitation: the Vulcan Dr. T'Pan, the Human Dr. Christopher, the Klingon Kurak, and the Takaran Jo'Bril.
Reyga installed his shielding aboard the shuttlecraft Justman, and Jo'Bril piloted the craft into the corona of the star Veytan. Although the shield worked, Jo'Bril sabotaged the test and faked his own death in order to discredit Reyga and steal the technology for use as a weapon. This apparent turn of events cast much doubt on Reyga's technology, and Dr. Crusher was forced to cancel all further testing aboard the Enterprise-D. Reyga was adamant that the shielding was flawless, and set out to find the cause of the problem.
Shortly thereafter, Reyga was found dead in an Enterprise-D science lab, the victim of a plasma surge in an apparent suicide. However, it had been Jo'Bril who had killed Reyga in order to make it appear that he could not accept the failure of his shielding and further discourage others from pursuing the technology. While awaiting the Ferengi ship sent to gather Reyga's remains, Dr. Crusher performed an autopsy on the body despite his family's forbidding it in accordance with Ferengi death rituals. The autopsy did not prove helpful in solving the case of Reyga's murder but Crusher discovered Jo'Bril's involvement shortly thereafter. (TNG: "Suspicions")
The script for "Suspicions" describes Reyga as, "not the typical volatile, argumentative Ferengi; rather, he projects an air of dignity and integrity." 
It took Slutsker three hours to get into his Ferengi makeup each day of filming. 
Reyga's metaphasic shield appears in the non-canon video game Star Trek Online, as a small craft shield array which is only attainable by purchasing a Ferengi Na'Far Shuttle. It grants a power which disables the ship's weapon and auxiliary subsystems, but increases damage resistances and converts a portion of all incoming energy damage to shield health.