What is it that lives if it is fed, and dies if you give it a drink?

Fire?

Explanation:

sounds familiar to a riddle that I've heard, but if it's not then I dont know

moon-letters were a method of writing invented by the dwarves. moon-letters were ordinary runes, but written in such a way that they could only be read when the light of the moon shone behind the writing. some moon-letters could be read by any moonlight, but it was possible to make the writing even more secret. more sophisticated moon-letters could only be read by the light of the same shape of moon, or at the same time of year, as when they were written. hope this !