Higher Justice

Before the Last War in Heaven. Before the angel Nicariel fell. He was a guardian angel, and one of Heaven's trusted servants. But when he finds himself forced to save yet another human charge who doesn't deserve to live, there are only two things he can do. Swallow down the rage and let another little part of himself die. Or make a deal with a demon. And accept the consequences. This prequel to the Nic Ward series is 5800 words long.
It is also available in Dark Wings, Bright Flame, an urban fantasy short story collection.