The Justicar's Heir (Aeonica #2)

Nahlia and Thane are fugitives.

Enemies surround them from every side. Not just Aeons and Templars, but a mysterious sect of assassins who seek the artifact they stole from Whitecliff.

During this time, Nahlia's powers grow faster than she'd ever imagined. But this growth brings new challenges, including a darker side of Ethermancy that could change everything

Meanwhile, Ciena Raider strikes out on her own. Driven by vengeance, she trains harder than ever before, vowing to become the strongest Aeon of this age.

https://davidmusk.com/books/aeonica-the-justicars-heir