Dragon-sickness

The Dragons of Middle-earth were greedy of gold, and they sought out hoards wherever they could, to keep and guard for themselves. Famously this was the cause of Smaug's descent on Erebor; lured by the immense wealth of the Dwarves who lived there, he sacked the Lonely Mountain and gathered its treasure in the Great Hall of Thráin.

Smaug dwelt within Erebor for a hundred and seventy-one years until he was eventually slain by Bard the Bowman. In that time, however, the gold on which he had lain had grown heavy with the Dragon-sickness, a sickness that affected those who came into contact with it. The Dragon-sickness was first¹ seen in Thorin Oakenshield, when he refused to provide for the slayer of the Dragon or his people.

The Dragon-sickness affected some more than others, and its effects were especially powerful on those who were already greedy and selfish. The most extreme case of this was the Master of Lake-town, who was given a part of Smaug's hoard to help in the rebuilding of Lake-town. Instead the Master took the gold and fled into the Waste, eventually dying of starvation.