Sonata Dusk is so happy that she and Adagio had decided to give up on returning to Equestria. After Aria left them 14 years ago and then she and Adagio find Aria happily married and with children.

Sonata and Adagio want to find the happiness their sister had found.

The Siren’s history and siren lore is loosely based on parts of:
Aria Archives and Dusk-Oceanos. Both discontinued comic on Tumblr.
Both by same author. Artistic license has been taken.

Many see Sonata as simple and naïve. But sometimes wisdom can be mistaken as foolishness.