[Awrya]

Originally Posted by ronelm2000

There's no said evidence of Kayaba's body being dead. ever. (only words from a programmed AI he created...right?) Of course feel free to try and prove me wrong.

Spoiler for Vol.4, Ch.8:

" - Are you alive?"
With that short question, I heard an answer after the briefest instant of silence.
『You could say that I am, and you could say that I'm not. In a sense, I am - an echo of Kayaba Akihiko's consciousness, an afterimage.』

and

Spoiler for Vo.4, Ch.9:

It seemed Kayaba had decided to die with the collapse of the world of SAO before the incident even occurred. But it was an unusual way to die. It seems he remodeled a FullDive machine to perform a super-high-power scan of his brain, where it burned out his brain and killed him.
The probability of the scan being successful wasn’t even 1 in 1000 - and, although it was baseless, she told me that in her heart she had the feeling that he somehow had succeeded.
If it worked as Kayaba intended, his own memories and thoughts, all of the electrical signals in his brain should have become digital code and should exist in the network as a real electronic brain.

Pretty certain that he is dead, if 4000 players died in SAO due to frying their brains, Kayaba isn't an exception. Confirmed by his assistant and the electronic copy of Kayaba himself.