Aincrad

Aincrad
Aincrad is the last area that you will unlock in the main game. It is an unfinished restoration of the original flying fortress by one of the two goddesses from the Sword Art Online. It is filled with high-level monsters that are generally hard to kill. This is an area with many zones in it. The different zones are as follows:
 * Unfinished Path
 * Unfinished Floor 1
 * Unfinished Floor 2
 * Unfinished Floor 3
 * Unfinished Depths

Upon reaching the Unfinished Depths you will be able to fight the final boss of the main game. Defeating him will unlock access to the addon "Warriors of the Sky" and its first area called Stalvatos Ruins.