The Dark Abyss
Journeying to End of the World drops you at the threshold of the Gate to the Dark. Head out of the small cave for a cutscene, and then set out to explore the vast expanse ahead of you. Despite there being very few visible areas to walk on, an invisible path stretches from stone to stone, so you can just walk normally. The various Treasure Chests scattered around contain some pretty awesome Items, but some will release dark orbs that will engulf your party and force you to battle some rather nasty Heartless (which you’ve fought before if you’ve already taken on the Hades Cup before coming here). Defeating them will reward you with the Item that should have been in the Treasure Chest.
Sometimes, dark orbs will simply fall from the sky in an unavoidable cutscene, which will again, force you to take on the native Heartless. When you reach the end of the Gate to the Dark area, a final dark orb will rain down and you’ll be forced to battle another Behemoth, this time with even more strength and HP than the one you fought during your second visit to Hollow Bastion. Defeating this Behemoth brings you to the Giant Crevasse area, which is absolutely enormous and full of nooks and crannies to explore.
There are many Treasure Chests scattered throughout the Giant Crevasse that will require the use of High Jump and Glide to reach. As an added bonus, there aren’t really any enemies in this area, making exploring that much easier. Your eventual target is a giant hole in the ground with swirling white mist pouring out of it. Use the Save Point close to the hole if you want to save, then jump right in.