The Monsters Within - The Monsters Series, #1

Sometimes the monsters are within us. The scent of burning flesh is more memorable than the ear-piercing screams that echo off the walls of The City-but both are etched in the minds of the innocent citizens who are stuck in the never-ending nightmare. Their only chance for peace is a young woman called Shadow-a rebel assassin known for her personal vendetta against the merciless tyrant who wants to be King.
Shadow must rush to stop him before he obtains an ancient magic and reigns over The City unchallenged. When tensions deepen during her mission to kill or be killed, Shadow must face the past she's been hiding from and the deadly enemies who hunt her, including a vengeful princess turned soldier, a Commander with a painful past, and a traitor that leaves her barely clinging to her life. And worst of all, she may need their help to succeed.
As war brews inside the Great City's walls, only one thing is certain: they will come to know the monsters within.