Raych Seldon is a twelve-year-old street urchin living in the rather lawless streets of Billibotton, a slum area of Dahl district. He meets Hari Seldon and Dors Venabili during The Flight. Raych takes the pair to a Mother Rittah. Hari and Dors adopt him. While he spends the rest of his life away from Billibotton, he continues to wear his knives and is quite proud of his Dahlite mustache.
When Raych grows up, he is infrequently asked by Hari to perform undercover work. While doing this work, and contributing much to the cause of Psychohistory, he meets his future wife Manella Seldon, with whom he has two children. One child, Wanda Seldon, will revolutionize Psychohistory with Mentalics. Raych will write a book on Dahl as an adult, and will be killed during a revolt in the Periphery.