Maoujou, Akibeya Arimasu!

In the magical world of Lockenheim, the Demon Lord Barbados and the hero Cygnar, rivals by fate, ripped open a space-time rift with their fierce battle, and the Demon Lord's entire castle is transported into our modern world. And, to their surprise, the place where they landed just happens to the building site for a future condo in Tokyo's Koto Ward! Our savvy (?) Demon Lord decides to rent out his castle as apartments. Now the Demon Lord must face the daily struggles of being a landlord in this new real estate comedy! (Source: Dengeki Maoh, translated)