Genbu

In the Land of Lightning, there is an unnamed remote island with many bizarre settings and animals, most notably the Falls of Truth. It is the training ground for Kumogakure ninja, and is considered to be the equivalent of Konoha's Forest of Death, aside from its superior size. The Fourth Raikage, and his younger brother Killer Bee trained on this island when they were younger. Killer Bee has has tamed all of the dangerous beasts, and also has a house shaped like the Eight-Tailed Giant Ox on the island. In the waters surrounding the island there was a Giant Squid that would attack anyone who traveled to the island. It is surrounded by a high-level barrier technique.

Trivia

 * Due to the apes and the very obscure settings on the island, it might be a reference to Skull Island from the 1933 film King Kong. Killer Bee also affectionately calls an ape "King", a reference to the film's title character.