Castalian

An intriguing, mythological choice that may appeal to fans of Caspian, Cassian, and Castiel, Castalian is the name of a sacred spring in Greek legend, situated near Delphi. The spring is said to be a place of cleansing, and also a source of poetic inspiration.

In some versions of mythology, the spring was originally a gift from the river Cephisus to a young nymph called Castalia, while in others, the spring was named after her after she flung herself into it and became a fountain, in order to escape the advances of Apollo. There are also other versions which suggest it was the site on which Apollo killed the monster, Python.

The exact etymology of the name is unknown, though theories include that it comes from katharos meaning "spotless, pure" or kassuo meaning "to sew, to stitch".

Pronounced kas-TAIL-yuhn.