Fractured Bonds by Kris Ruhler

Enter the lion’s den. Find the cure. Rescue her guardian. A simple mission, except they’d been waiting for her… Reeling from the battle with the Jinns, Khara splits up with the team. She heads to the walled-off city of Cerulis to find Belor and a cure for her deepest fear—the Other.
A being that lies dormant within her.
A ruthless fighter who has no qualms about hurting the people she loves.
But Cerulis city poses a challenge, and the Sanctum Labs are impregnable. Even worse is the threat of the Mythren army marching toward them. Khara finds herself running for her life.
But where can she run when the Cerulian scientists can control her with the push of a button?
A story about integrity, identity, and a flawed heroine.
Welcome to the Aeterna Chronicles.