Before he was known as Mehmet... he was called Lucifer. Here's the story of how he fell.
When angels appear in Celestia's groves as malformed and without wings, they're cast out of paradise and into the darkness below. Lucifer has been charged to roam the Birthing Forests and find a child of his own, only to watch the wingless angel be discarded. There's only one way he can save them...
Lucifer's Fall is a short story written in the same world as the Celestial Downfall trilogy.