When Herman and Manny first met, Manny was a newborn. Then Herman adopted him.
There was no circus then, and Fuller started with tricks, gradually gaining a team. It was when Manny came along that Fuller got the idea for the freak circus. Herman wanted to give the child a big, loving family.
I don’t take it upon myself to justify Fuller’s atrocities, but I don’t think he deserved what happened to him in ‘curtain call’. So here is a happy ending to this story!: Manny saved his old man, the circus forgave him, and now Manny cares for Herman the way Fuller cared for the baby with the upside-down face in his days.