Range of Mercy by C. C. Marks
Summary: Saving the world on a daily basis didn’t make you a hero. Thomas Morgan knew that much from experience. The hard decisions he was forced to make weren’t pretty and not all that heroic. He was the one who did whatever it took to maintain security. Each day he climbed into the guard tower and kept the microcosm that was the community safe from Draghoul, the once-human monsters that attacked every night. More importantly, he watched out for the vulnerable, especially Charlie and her sister Star.
Charlie disguised herself as a boy, but Thomas knew the truth, and though she wasn’t aware and though it put them all in danger, he kept her secret from the others. Reality was harsh in this unmerciful world, and she didn’t stand a chance against the schemes of the self-appointed leader, Jonas Bannon, if he ever figured out the truth. Doing the right thing didn’t make Thomas a hero. But it did keep him human, and it did put him in range of mercy.