Kongoukai

Kongoukai (ダイヤモンドレルム; lit. Diamond Realm) is a series of pocket dimensions in Soul Society. They can only be entered by artificial means, which are known only by the cult organization, the Inboyuigon. During a shadow war, the Sixth Division and the Tenth Division of the Gotei 13 broke into Kongoukai to combat the Inboyuigon.