Mictecacihuatl (pronounced Meekteckaseewadl), also known as the Lady of the Dead, was the Aztec goddess of Death. I haven’t been able to find out for certain whether she died as her mother gave birth to her, or was sacrificed to the gods as a small child, but either way she died young and grew to adulthood in the Afterlife.
According to Aztec legends, the human race was created from the bones of a previous race, which had been stolen by the gods. To prevent this happening again, Mictecacihuatl, who was now the Queen of the Underworld, was tasked with guarding the bones of the dead so that they could never be stolen to create a future race.
Related post: The Day of the Dead