When Demeter's daughter went with Hades to Tartarus, there was a dog who keened for the loss of her from dawn to dusk. After some days, where other humans and gods attempted to comfort the dog, a woman, much changed but still familiar, approached.

"I have heard your lament, little puppy, and I have one question for you: Would you like to be my protector and the hound that guards the door between my worlds?"