He Who Vowed to Create a Demon Harem

What happens when a hero falls for the demons he’s supposed to destroy? Strange circumstances bring a human hero together with three demons, and the four of them set out on the adventure of a lifetime. They don’t work well together at first, but after a while (and with a little help from a special item), these old enemies will start to REALLY get along… The year is 1887. Humankind has been assailed by demonic invaders from hell. For a time, humanity’s future was uncertain… until brave soldiers arose who fought back the demons. These soldiers are called heroes. One such hero, a man named Theo, has a goal in mind: take back the city of Manc from the demons who control it, the Halfas family. But the daughters of said family ended up being a lot cuter than he expected…