The first part of the quote ("Its surface blazes bright") connected in my mind to the first quest where we learn of Light's Heart. Khadgar says,
"The Order of the Silver Hand have reported that an extraordinarily luminescent object has emerged from the Felstorm and is currently falling towards the coast of Suramar. What I find most curious about this occurrence is that the object was reported as having 'cut a swath' through the Felstorm itself."
At this point, all we have is the word of a pre-recorded message that came with the core. In the book of his namesake, Illidan attempts to locate Kil'jaeden on Argus using his astral form, all the while a mysterious presence is following and watching him. Almost as soon as Illidan finds Kil'jaeden, the Deceiver senses him and the mysterious presence begins to ensnare him.
The Deceiver's gaze rested there, pregnant with the threat of destruction; then it passed on. Something had turned it away from Illidan, and it took him a moment to realize what. The presence that enshrouded him now pushed him out of the edge of the throne room. He had a sense of it just for an instant. It was a thing of Light, so bright as almost to be painful to behold. As he became aware of it, he heard a titanic roar of rage from within the throne room of Kil'jaeden, as if the eredar lord sensed it, too.
though he later adds:
And he had found something else, a being who had aided him to escape when all seemed lost. He thought about the Light he had sensed within it and realized he did not trust the thing. Kil'jaeden was not known as the Deceiver for nothing. Perhaps this was all part of some vast and elaborate trap.
Hey I'm absolutely open to either possibility, but do you have any speculation about what the three lies will be? I think that identifying those will clue us in to who the "boy-king" really is.