Who are you? Jon asked the figure.
The formless shimmer began to take on a more recognizable form - that of a man, actually. And then the figure himself became recognizable.
Grandpa? Jon asked, shocked at seeing his dead grandfather. Although, maybe it shouldn't have been much of a shock, since Jon and his grandfather were now both dead.
That's right, Jon. It's me, his grandfather said (or rather, thought - his mouth didn't seem to move, but Jon heard his voice, nonetheless). I've been watching over you ever since you inherited the stone from me.
You've been with me the whole time? Jon asked.
Yes, he replied, nodding.