The apartment has a strong Japanese theme, with tatami mats, shoji, and fusuma doors.
The living room includes various training equipment for Black☆Star and a low chabudai table, with a small alcove with a jar of flowers before a scroll hung up on the wall with Japanese calligraphy, its kanji translated as "Sky above, sky below, I alone stand almighty," a phrase suitable to Black☆Star's effort to surpass god. Appropriately, another scroll in the living room has calligraphy reading "God."
The apartment likely includes a kitchen or another location for cooking, as Tsubaki prepares meals as rewards for Black☆Star studying, and for social gatherings such as at Gallows Mansion. The bathroom is made of wood, with a large bathtub and a bamboo fountain-like tap. As Black☆Star tells Kilik, due to the lack of rooms in their apartment, he and Tsubaki share a bedroom.