NXGen Research Facility is first mentioned by Seraphina's Maid. Seraphina's father, a business partner of NXGen, wanted his daughter to apply for an internship there, but her application was rejected.
During the Monster Arc, the Newscaster reported that two months prior, a top secret research project funded and led by the authorities that NXGen was working on had been put on hold, and much of the research data and equipment was either stolen or destroyed, leading to a hiring freeze.
Currently, none of the employees of NXGen are known. However, Seraphina's father is their business partner and he knows them well enough to get his daughter an interview for an internship with them, despite their hiring freeze.
NXGen specialises in the research of the root of abilities. It is not known what they have discovered so far.
NXGen probably comes from the phrase "Next Generation", referring either to the company's futuristic and ambitious goals or how their research will benefit future generations.