Who is The Gravedigger from Christ Stopped at Eboli and what is their importance?

A quiet, ninety-year old man, the town gravedigger was regarded by the townspeople as something more than a man. They said he could tame wolves and speak to the animals and spirits in the village and surrounding areas. Carlo talks with him on several occasions, but the man is nearly incomprehensible. Carlo wonders if the man fought in the brigand wars as he seems to remember vividly meeting one of the most famous brigand generals, Ninco Nanco.