This is a fanfic which takes place in the world of ACOTAR.  It takes place more than 500 years into the future of Prythian.  I made up an under the sea realm in the eastern strait between Prythian and the continent. The main characters are from the realm under the sea, Spring Court, and Night Court with supporting characters from Autumn Court and Dawn Court.  Yes, it is partially inspired by a classic Hans Christian Anderson fairy tale about a maiden from under the sea.