There are two of them, but they are the same person. It is not a usual situation, even among Bonded dragons. (He clarifies the concept so that she does not have to rely on an imprecise categorical description formed in worlds other than this one: this is what local dragons look like, this is what it feels like to be one, and here is the feeling of recognizing a Dragonbond, and the function the Bond has in allowing the dragon to reproduce and allowing their Bonded to do arbitrary amounts of magic without cost—)

But while Bonded dragons are usually less vulnerable than their Bondmates, this dragon's Bondmate is (uniquely among all people who have ever Bonded to dragons, as far as he knows) an Endarkened (distant impression of a very long time spent in very unpleasant conditions), and therefore near-literally impossible to kill, unless you happen to have a unicorn handy (the burn of a unicorn's horn, an incandescent blaze of pain across the palm of his hand).