Is Kayaba Akihiko the boss of the 100th floor of New Aincrad? 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?
To my understanding New Aincrad's Floor 100 has to to be revealed however the likelihood that it's Akihiko Kayaba is low.


After Sword Art Online was cleared Kayaba did a full dive and it was reported that he was killed in the process. it can be speculated that the Full Dive was successful however there is no evidence to definitely prove that Kayaba is alive
New Aincrad was released by Ymir, the company that now own Alfheim Online. the data from New Aincrad pre-exited on the Alfhiem Online Serves because of how ALO is a copy of SAO, however Aincrad had been altered.



  Due to the bought ALO data including copied data from the old Sword Art Online server, New Aincrad (with several changes from the original Aincrad in SAO) and Sword Skills were introduced into ALfheim Online and surviving SAO players were able to inherit their avatar data from SAO. 


Source: Ymir - Background (Second Paragraph)


The Floors of New Aincrad are being slowly released so there is an upper limit until an update. this is evident in Sword Art Online 2 Episode 18 where Agil shows Kirito and Asuna the release notes for the next ALO update, including the introduction of the 21st-30th floors of New Aincrad. so at the moment (as of the end of Sword Art Online 2, I haven't read the Novels) no one can access Floor 100. if i was to speculate there is no data for Floor 100 (except for the outside appearance for the sake of scenery) until the update is released