Long ago, when the World was new and ponies were just starting to make civilization, the alicorns came down from the clouds to help the ponies learn what they learned long ago. splitting off into their own sections of expertise. The ponies considered these "pure" beings to be gods. Some protested this, claiming they were just normal ponies, while others basked in the title. either way they were above the ponies of the land according to the ponies of the land.

Amoung these "Gods" was Neptune. Their job was to watch over the sea faiers, teaching them how to build vessels for the sea and using their magic to move the moon and control the tides, and use move the stars in the sky to be the guiding light to lead them to safety. For centuries Neptune worked with the ponies, add eventually created the sirens and seaponies to aid them as the population grew. Temples in the sea were built in their honor. Though after a great storm appeared, they, along with all the others, were never seen in broad daylight again. only 5 alicorn foals remained.

Despite not being there in the physical sense locked away in a personal dimension like all the other Alicorns. They always kept careful watch over the sea fairing ponies, particularly sea ponies. In the honor of them they took their place of guiding lost. Many Sea creatures and sea fairing ponies still worship them. and if you're a lost sailor, you may just find a temple of them sitting in the ocean with a map inside to guide you home.