Leviathan's Lament. Depths Duology, #2

Grey thought her life couldn't get weirder than it has been the past four years. After all, what could beat a couple of sudden gender swaps, a cursed island, and finding out your mother is a siren? Funny, Grey. Real funny. For starters, the rock that connects Grey to Etna Island? Turns out it might have something much darker attached to it-something all the other supernaturals insist a mixed breed like Grey isn't strong enough to handle.
Oh, and then there's the band's growing popularity and the possibility that Grey's love life might destroy Lucifer and everything they've built. Leviathan's Lament is the last book in the Depths duology. Author's Note (Really, Read it): *Leviathan's Lament is book 2 of 2 in the Depths duet. It is poly/reverse harem romance, and contains M/M, F/F, MMMMFF and poly themes. The heat level in this book is quite a bit higher than book 1.*This is a full length novel, but is shorter than book 1, at a little over 80, 000 words.
Contains no filler or fluff sample chapters at the end.*This book contains adult language, graphic sexual situations, and touches on sensitive topics. Do not read if you are easily triggered. Contains talk of, but no "on-the-page" details regarding suicide. Contains discussion of mind-control and talk of sexual situations under mind-control that occurred in the first book (not horribly graphic, but may be a trigger for some).
I believe in happily ever after-but sometimes the road there is rough.*Examines stereotypes and ingrained beliefs about sexuality and gender, as they pertain to the plot of the story.*Contains one non-human character with non-standard anatomy.*Final book. Complete series. No cliff hanger.