Kobolds are sprites in Germanic myth, usually invisible and able to take the shape of children, small fire elementals, animals and candles. They haunt mines or live in people's houses.
in D&D, they got turned into sneaky, small, dog like critters who are good at trap making. They kept their underground habitats from folklore. They mutated into lizard like critters in 3e, and then started worshipping dragons, with some kobolds being born with wings.
A few years ago, I was tracking down letter tracing sheets for my kindergarten class, and found "K is for kobold," with a picture of a D&D style lizard kobold. Made me smile.