Sanctuary of the shadow : the Elemental Emergence series
(Book)

Content warning: "The story includes elements that might not be suitable for all readers. Sex, violence, imprisonment, bodily injury, memory loss, parental death, and coercion are mentioned and shown in the novel"--Publisher's website.

"Harrow was born during a war between two of the five capricious Elemental Queens. It's a war of fury and attrition, and exacted its price in blood. In one grim night, almost all of the water Elementals--the Seers--were killed. All but Harrow. Years later, she's taken refuge in anonymity, hidden within an unusual circus run by a centuries-old Enchanter. No one can know who she really is or about the magic she wields. Now the circus has acquired a new 'attraction.' A creature dark as night, with wings, and inky black eyes that dance with fire. An elemental with no recollection of who he is. Some think he's a monster. Others think he's a myth come to life. But Harrow's magic knows he's something else ... if she can unlock his memory"--,Provided by publisher.