Richard Pryor is sort of the archetype of the comic with the dark side. Like Don Draper, he grew up in a brothel where his mom worked. And he apparently stumbled out with more talent than he knew what to do with.
Moving to New York City in 1963, Pryor immediately began performing both in comedy but also in singing, where he opened for Bob Dylan and Nina Simone. Simone recalls of his performance anxiety, He shook like he had malaria, he was so nervous. I couldnt bear to watch him shiver, so I put my arms around him there in the dark and rocked him like a baby until he calmed down.