On page 36 he says, "The student of Talmud, the child I was, had been consumed by the flames. All that was left was a shape that resembled me. My soul had been invaded--and devoured-- by a black flame." by this he means...
He feels as though his experiences have destroyed the strong faith he had in his religion
He was forced into a fire pit and was burned badly.
He has been starved and abused so intensely that his physical appearance has changed.