An excellent, and difficult question, friend Grim. Here is what I know or have heard of the stone:
When Dissonance had only just appeared, before he acquired his more towering aspect, something like two winters ago, I was walking one night, not far from Gypsy Row, and I saw a gleam of red in the trees. I investigated. I found the swirling, sickening field of tiny red spots I have since come to associate with Dissonance's magic. I don't recall if it was that same night or shortly after, but he emerged from the stone and spoke to me. That day, or the next, I investigated more closely in the light. This was very shortly after Bernard had used explosives to reveal the entrance to the catacombs, and I thought perhaps the stone had been thrown from the explosion. As it happened, the rock looks to be of an entirely different type, but it did indeed sit in a shallow crater, and seemed to have been thrown from someplace, or fallen from some height. There was no circle about it then, and foolishly, I touched it. I was overwhelmed with horrific visions of death and destruction, until I was either thrown clear or momentarily lost my senses. Later, of course, it was encircled, and the connection between it and Dissonance became apparent.
I have since spoken to brave Widjan who have traveled through the mists in investigation, and they have shared a theory with me, which I shall try to relate, though I lack their wisdom in such matters. It was their belief that the stone is a shard of a magical element known as “void,” perhaps thrown through the mists to come to rest where it now sits. Apparently, such “Void shards” can produce guardians to protect themselves. It was suggested that Dissonance could, perhaps be such a guardian.
(It bears mentioning that Void's opposite, incidentally, is the substance known as “Puriel.” As you might recall, the verse of song that's been used against Dissonance mentions Puriel. If this theory is correct, some item of Puriel, perhaps in the shape of a weapon, will likewise have been called into existence. But I digress. It was the stone you asked about, not the foul beast I exist to destroy.
So what is the relationship, if any, between Ravinious and Dissonance? Given our ignorance, anything is possible.
Perhaps, if the Widjan theory is correct, Ravenious, a powerful sorcerer,may have somehow employed the void shard and its guardian, either taking advantage of the shard's fortuitous arrival, or coming here to utilize it, or somehow bringing it hither.
More simply, perhaps Ravenious has either conjured or attracted Dissonance himself, but this leaves the stone out of the picture, along with many other features of the dark beast: the connection to music, the use of other beings, the magically binding bargains, and the occasional painful distortion of free beings, as has happened briefly to Arbiter Harris and myself. Again I drift into my obsession. Forgive me.
Teovel Armonia
OOG:Scott Auden