Here's Where Billy Maximoff Fits Into The MCU After The "Agatha All Along" Finale

Ain't life a witch? 

Episode 9, "Maiden Mother Crone," shows Agatha, years after she killed her coven, traveling from town to town with her son Nicholas "Nicky" Scratch - whom she made, yes, from scratch. No magic. This immediately puts a target on his back from Death, but she allows Agatha to have an undetermined amount of time with him. 

Agatha and Nicky create "The Ballad of the Witches' Road" as a little ditty between them. Agatha uses Nicky's angelic voice and their song about a Witches' Road to lure curious witches into Agatha's power-zapping traps.

Eventually, Death spirits Nicky away from Agatha, and Agatha turns her grief into centuries of killing, letting "The Ballad of the Witches Road" become witch lore from which she preys and benefits.