Kangoku Island (監獄諸島,Kangoku Shotō. Literally Meaning “Prison Island”) was originally named Kangoku Prison, it was used by the Wano Country government, to lock away all of their worse crimes. It was said to be Wano Country’s version of Impel Down, however the island had fallen under the control of Warden Cho Cho. But after the Itsubetasijo had attacked the island and claimed it as their own, it is now their main headquarters. The Kangoku prison staff now has been put under the group thumbs and now are the guardians of the complex and island. Whenever none of the Itsubetasijo is around, Cho Cho has been given command of the island.