The Yappari  Chronicles is a series of fantasy novels (currently three books) that take place in two distinct environments in the same world:  one on dry land in the fragments of what was once the sidhe empire and the other underwater, in the Yappari Empire and their strictly matrilineal society that has taken over the vast expanse of the oceans. 

They can be purchased on AMAZON:

Winterborn (2010): 

Generations after the sidhe empire’s clan wars caused their obliteration, the remnants of their creations come back to haunt their descendants. With magic gone unpredictably wild, it’s up to Mirin and Tereg ( a rogue fire mage and the pickpocket he rescued) to either save what is left of the Empire or to destroy it altogether.

Battersea (2019):

When Salo, son of Matron Iona of the Yappari, goes missing both the Yappari Empire and the Sidhe clans are thrown into upheaval. Matron calls on the debt owed to her by Mirin, a Yappari renegade living among the sidhe in order to find him and prevent all-out war.  As wyrms and sea dwellers take sides in the brewing conflict, Salo may be hard-pressed to escape with his life…never mind safeguard the House that sired him.

Distant Shores (2019):

With the civil war between Yappari Houses spilling over into dry land and the vast expanse and various peoples of the Reach, the newly crowned Matron Sanhadrin and her cousin Salo have to find a way to cement her power and alliances… potentially at the cost of those few she truly treasures.