They Come at Night by Nathan Zimmerman

Colonel Dillon O’Connor is a failure who stands on the edge of redemption. After relegation to the slums of NYC, Dillon quickly discovers his new apartment building is teeming with the embodiment of humanity’s dark seed. Without immediate intervention, the tenants of 143 Dresden Avenue will be eaten alive. Dillon has the means to prevent a massacre, but his better judgment lies beyond a battlefield of apathy for the human race.