Green dragon of beacon

YN grew up in a life of luxury and privilege. He had little interest in the family's illegal businesses, and although he excelled at and enjoyed his ninja training, he spent most of his time pursuing a playboy lifestyle. Many within the clan considered the carefree YN to be a dangerous liability, and they resented his father for coddling and protecting him. Following the clan leader's untimely death, YN older brother, Hanzo confronted him as tensions rose the confrontation that left Genji on the verge of dying, however he was saved thanks to atlas tech and cybernetics, after therapy to help cope with the change he received training from the huntsman special opps group code named overwatch and made friends with some of the other overwatch trainees, when he got old enough he and some of those friends were sent off the
beacon to become official huntsmen

(Basically overwatch chooses young trainees to take in and train like as an advanced combat school before they go to a huntsman academy)