In the anime Sword Art Online, the floors from 76-100 have been untouched since Kirito beat Kayaba, but before Kirito does so, Kayaba Akihiko said, "I was meant to be the final boss at the 100th floor."
Now that there is a New Aincrad built in Alfheim Online.
Is it possible that Kayaba Akihiko is waiting on the 100th floor for a rematch? Or could the end boss just be another random boss for them to fight?