Rasetsu lives by himself in a seedy crime-filled part of Nagoya. It is a dangerous slum area where the yakuza and various other crime syndicates take advantage of. There is a lot of gang violence and illegal activity where he lives, so Rasetsu lives in the safest place there; above a ramen restaraunt, or at least that's what it looks like on the outside. The truth is, Rasetsu lives on the upper level, in a single room, single bed, and single bathroom apartment. The rest of the complex is a place for "less than reputable activity" including drug dealing/usage, prostitution, money laundering and weapons trading. Part of why Rasetsu has no friends, or rather, why he doesn't let anyone get close to him is the place he lives.
Basically under no circumstance's would you want to go to this place. It is more like a box than a suitable living space having only the essentials. As soon as you walk in you see the bedroom, table, and microwave, with a small TV at the end of the bed which only gets public access. There is only one other room and that is the bathroom, other than that there is really nothing going on in here.