I'm working on the Black Mage relic quest, and while my memory's a bit fuzzy, here's what I remember:

The witch Shatotto (otherwise known as "Death's Handmaiden", among other pleasant names you're told from the BLM questline) was a master of magic. So much so that she was rather bored with casting 'mundane' spells. So she did some research and discovered a spell that allowed her to pluck a star from the sky and send it crashing to Eorzea. And that's precisely what she did (in the name of boredom, mind you): send a meteor plummeting into the planet. Her plan succeeded, and from that meteor she took a fragment of it and used it to craft her weapon, the Stardust Rod.

The things you can do when you're bored, huh?