A luxury yet wrecked building with various floors of height, a Devil training arena, hot springs, and various rooms with valuables that Kawajiri got during his years as a Devil.
The place is filled with Cactus, having them on the roof, kitchen, and hall.
It its unknown for how long Kawajiri had the place but its mostly assumed he got it after his Devil ascension. Nikaido used to visit him and for some time before her permanent residence in Hole, she lived and trained perfecting her martial arts there.
Once Kawajiri was demoted from his Devilhood and rescued Nikaido from her imprisonment in En's Mansion, they spent a month training to make Nikaido able to propperly use her time magic. After a series of events Risu ended living there too as a petition made by Aikawa to Nikaido in oder to ensure Risu's escape from the Cross-Eyes.
The trio lived there in quite dysfunctional way thanks to the recurrent teases made by Kawajiri to Risu, mocking him for be poor, lame, a Cross-Eyes and pretty useless as a Magic User (all thanks to his mischievous Devil nature, even if he tried his best to be nice with Risu).
Once Nikaido fully mastered her magic powers partially evolving into a Devil, she released a humongous amount of smoke, the barrage destroyed the place and created her Magic Time Box, everyone had to escape to Hole and live in the Hungry Bug.