Other Characteristics
All of Tolkien's dragons share a love of treasure (especially gold), subtle intelligence, immense cunning, great physical strength, and a hypnotic power called "dragon-spell". They are extremely powerful and dangerous, though they mature very slowly. Because of this, Melkor's first attempts to use them against his enemies fail, as they are not yet powerful enough to be useful in battle. Despite their evil beginnings, they are not purely destructive by nature, as can be seen by Smaug, who wants to be left in peace, though he did force out the dwarves in the Lonely Mountain.
Dragon-fire (even that of Ancalagon the Black) is described as not being hot enough to melt the One Ring; however, four of the Dwarven Rings are consumed by Dragon-fire.
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