Heir: Immortals of Indriell (Emerge #4)

The last Immortal Queen of Indriell has named her heir.
The title means nothing to Allie Carmichael. Nothing but more drama and attention she never asked for.
Allie loves her newly discovered royal grandparents, but she just wants to finish her senior year of college and start her first job. Not step forward as the princess of a long dead nation she knows precious little about.
At twenty-one, she considers herself an adult and has finally found the normal life she’s always craved. As normal as it gets for a young Immortal legacy—prophecy or not.
For years, Allie and Aidan have gone their separate ways, doing the college thing and just living their lives. Apart. It was his choice to sever their ties. A sacrifice to give her the time she needed to come to terms with her bond with his brother, Darius. A sacrifice she’s come to believe was necessary for all of them.
But when Allie discovers that Aidan hasn’t been in school all this time—and his family hasn’t heard from him in more than a year, she struggles to contain her rage and the powerful judgment that burns within her.
Protecting Aidan, even from himself, fuels her every breath. She would do anything for him. Even step forward as the heir.

The Mortal Instruments meets Red Queen in the Immortals of Indriell, a series of dark, paranormal fantasy tales.