Avery. If you thought the first two Nicolis were complicated it's nothing compaired to Avery. He has his secrets and keeps everthing to himself, never letting anyone in even his brother.
Emeline was a part of a secret order to keep an eye on decendants of Egyptian gods, but that al ended when her Grand needed her to take care of him. Her last job was to keep an eye on Avery and now forced back into doing the orders bidding she's supposed to gain his trust and betray him. But even before thier offical meeting she knew she could never do it, but what will happen when they come together and what happens when he discovers her secrets.
Avery is strong, silent, dangerious and angry. Keeping his anger in check is a chore but he does the best he can. He's also honorable and for those he cares about he would do anything.
Emeline is headstrong, but she also has great inner strength. She tries to do everything herself because she doesn't want anyone else to get hurt.
Where Avery opens up to protect those he loves Eme is closed of in order to protect them. They have their share of troubles, and it's quite a journey to see them figure everything out.
We see more of the storyline continued from the first two books and we understand more and see where the story will take us in the future.