If you read this as the announcement of a new series I'm planning to write, you would be correct.
What inspired this?
I love the retellings I'm seeing at the moment and I want to get in on that action. The Little Mermaid was my favorite Disney book growing up (that was before I knew about the Hans Christian Andersen origins) so that was very much my thinking here.
I originally wanted to go with this book from Ursula the sea witches' point of view, and how she's so misunderstood and painted as the bad guy unfairly. But then I realized this is basically the plot of the musical Wicked. So I'm still busy working out some of the key plot points, before I start building this world (yes it will be set underwater partially) so it's really going to test my world-building skills.
In terms of where does this sit in my book release schedule, I'm still working that out too, but I'm most likely going to release the first book in the series in 2024, possibly between the second and third book of The War of the Witch Clans.
So keep an eye on my book release schedule, you may see the first book sooner than you realise.