Jacob has always lived in the chamber in the statue. His enemy was trapped in the cabin by Jacob. When the circle of ash was broken, his enemy escaped to the chamber to kill Jacob.
Jacob's firepit seems to consist of burning grey ash. The ash in his firepit which seems to burn eternally without added fuel looks very similar to, and may in fact be the same substance as, the grey ash circle which surrounds Jacob's cabin.
Jacob's chamber was lightly furnished in 2007 because he had moved his primary residence elsewhere.