A man walks out of a house that has four walls all facing north. A... Riddle

His eyes were raging, that scraggly beast.
His lips were bursting, with rows of angry teeth.
Upon his back a razor was found.
It was a fearsome battle we fought,
my life – or his, one would be bought.
And when we were through,
and death chilled the air,
we cut out his heart, and ate it with flair.

It is able to speak because it has a hard gone. You know what it is as soon as it has sung. What is it?

The older this thing grows the more valued it becomes. It is always much better when its breathing is done.