The Devil has converted a tenement building into monsters-only housing in Unholy Heights, a mashup of Tower Defense and Apartment Management Simulation. Sucker monsters into moving into your building, charge them rent and keep them happy by buying them furniture.
Unfortunately, heroes have caught wind of the Devil's plan, and will stop at nothing to wipe him out. Knock on residents' doors to call them to battle, trap heroes in devious pincer formations, and command your troops to victory. Monsters get jobs, fall in love, have children, and even skip out on their rent. Keep them happy or you might not have anyone to fight for you when heroes come knocking.
Being a landlord is a difficult job, but it can't be harder than running Hell...right?