[The Squatter of Amon Rûdh]

That's Andrew Lang, the Victorian philologist and compiler of variously coloured Fairy Books. Tolkien quotes him in On Fairy-Stories on the subject of mercy and justice in the realm of Faerie.

Andrew Lang was confused on this point. He was at pains to defend the slaying of the Yellow Dwarf by Prince Ricardo in one of his own fairy-stories. 'I hate cruelty,' he said, '...but that was in a fair fight, sword in hand, and the dwarf, peace to his ashes! died in harness.'