Supernatural 18+ romance

It's a novel about creatures such as vampires, wolves, Amazons and other supernatural beings were summoned to an island by Gods to fight each other but a vampire and amazon end up falling in love and being the last participants left in the game. I think they defeat the gods and rescue all the other creatures.
At a point the Amazon forgets the vampire.
I'm not 100% sure it's Amazon but I remember she was from a realm where only women dwell like wonder woman kind of thing.
That's all I remember