World of Chaos

The World of Chaos is the name of the true final boss in Kingdom Hearts.

The World of Chaos is a giant, biological Heartless battleship that Ansem bonded himself to as his final form. Capturing Donald and Goofy, Sora was forced to fight Ansem on his own until he retracted into his Guardian. But after getting his friends out and destroying the Core, Ansem reawakened to fight the three off before they did enough damage to destroy the World of Chaos and forced Ansem to separate himself from it, leaving him mortally weakened as a result. During the battle with it Ansem wielded a large double-bladed Soul Eater pole arm. He could also shoot lasers from virtually anywhere in the room, as well as the ability to throw Bit Snipers (Final Mix) or call on Bit Snipers at any time (Kingdom Hearts). His ultimate attack consists of blowing Sora away and connects by firing countless destructive lasers tracking Sora.

Room Core
There are three room cores. One is by yourself and the other two are with your allies. These are only able to be attacked by destroying all the Heartless in the room. No matter how high your strength is, you can destroy it using one combo, on of three hits.

Artillery
Artillery is a Heartless that appeared on the World of Chaos. They are bluish organic cannons that are attached to the World of Chaos, and shoot blue blasts of energy at Sora as he flies by. A stronger version of them are also present, called Heavy Artillery. When they are destroyed by Sora, Donald, and Goofy, another set respawns after a certain time, but within the time when they're gone attacking the World of Chaos becomes a more manageable task.

Face
The Face is on the front of the World of Chaos, Ansem's true form. Sora and Goofy must defeat the Face before rescuing Donald during the Final Battle of Kingdom Hearts. The Face's attacks are fierce and powerful, with vicious bites and powerful energy blasts. However, Sora and Goofy prevailed in the end.

A good strategy for defeating Face is to cast Aeroga on Sora and attack with combos, but keep your MP up to cast Curaga etc. The face seems to be one of Ansem's minions that he summons to his aid in the fight against Sora. The Face will frequently open its mouth and release lightning bolts from the sky (a la Thunder,) that will automatically seek out and strike Sora from above no matter where he is. The only way to dodge them is to glide around the area. On top of that, many missile shooters can harm you, so stay alert. When the Face's HP is depleted, you will have to enter the Mouth of the Face to fight more Heartless and rescue Donald, then you will be able to attack the central energy core of the World of Chaos Heartless.

Main Core
The Main Core is the "heart" of the World of Chaos. It is reached when you have been reunited with Donald and Goofy after the fight with Xehanort's Heartless the first time around. There isn't really much of a strategy to this fight, all you really need to do is whack at the heart and block the lasers coming from the tentacles shooting lasers or destroy the defenses. It looks like some sort of a face of a cat(or something like that) and it somewhat sort of shaped like a "blob" and it moves when you hit it.

Battle Quotes
"Turn to Darkness!" "Welcome the Darkness in your Heart." "All shall be extinguished." "Still confused? Then perhaps this will enlighten you." "Come forth!" "Weak ones, witness real power!" "Come...Darkness!" "Is this the answer? It cannot be!"