Name of world: City of Ragnaton
What it is like: a huge city the size of a kingdom that has day and night. This city is also where the Keyblade was said to originate from. In this city keyblade wielders power increase dramatically. during the day this city is extremely peaceful and undestirbed but at night the leader of this world set up a curfew for everyone who reside in it because here is where heartless and nobodys are most powerfull. The soilders and officers of this city are mostly Keyblade wielders, swordmen, and master summoners. This place is extremely dangerous at night. Those without weapon or strong power are easily killed.
History, or how does this get unlocked: This place can be accsesed from quite a number of places. A portal in the basement of World That never Was, A portal in the cave of the Oasis, a portal in the World of the Keyblades, and also portals in any of the Final Fantasy Worlds. (note you can not make your own portal to this world unless you have visited there once and got approval from the king of this world)
pic of me summoning many keyblades while being confonted by heartless: http://img.gamespot.com/gamespot/images/2006/127/reviews/932981_20060508_screen002.jpg