Malazan Empire: Kellanved and Dancer's origins - Malazan Empire

The following information appears on GoTM, but I've decided to start this disscussion here, since it would involve revealing the information that K&D are Ammanas and Cotillion.Anyway, when Sorry gets close to Lorn in the Gadrobi Hills, we see that she has unpleasant memories from Otataral.Now, I guess these memories are from Dancer, since Sorry seemed aware of her been the Rope.So...what exactly happened with Dancer and Otataral? maybe he visited the mines without knowing how it would affect him, and it daamged his ability as a mage.I assume that he was a High Mage as well as an assassin, same with Surly, whereas Kellanved was just a High Mage, we get to see the difference with people like Vorcan and Topper.
Another thing, when Paran is stabbed, Shadowthrone comes and talk, his accent reminds Paran of a Dal Honese trader.I though Kellanved was a Malaz City native, but maybe he came from Dal Hon.Or maybe...Iskaral Pust is Shadowthrone? guess not.