So the Brass God would be used as a divine skin and the souls of the Dwemer would be used to create it. So that is why they disappeared, because they sacrificed their souls to make their Brass God which they would use to return to the "first brush of Anu-Padomay", and basically be, 'anti-created'. But why would they think that they had to all become one with this Brass God in order to do this, well the answer was right there in front of me. As the Altmeri creation myth states, the Mundus was created as a place where the aspects of the Aspects could reflect on themselves. So to return to the state of the original Aspects of Aurbis, the aspects of Mundus would need to be forced back together into their former shape, or something close to this. So the Dwemer with this in mind, began the creation of the body of their god, the would-be Aspect of Aurbis, with the Heart of the World, the Heart of Lorkhan, as its heart and main power supply. They then planned on combining their entire race with this god in order to anti-create their way back to the Aurbis, their many aspects as Dwemer would be reverted back into godly form as one singular Aspect.
Now Xal states that the souls became Anumidum's metal body, but you ask, why would they do this. Well, this is where the Earthbones that Demnevanni spoke of come into play. Dwemeri metal was no ordinary metal, as Baladas stated, it could defeat time and decay. The Dwemeri souls would become immortal in this state, and at the same time become one to form their god. Kagrenac hit the Heart with the tools during the Battle of Red Mountain and caused this to happen, and the Dwemer disappeared, just as he had intended for them to. But why did the Brass God stay, why wasn't it activated as a god once the Dwemer became one with it. That I do not know. Perhaps it was the Tribunal there that stopped this from occurring, disconnecting the god before it could leave. Perhaps Kagrenac simply didn't see far enough ahead and more than just binding all the Dwemeri souls together to form a god wasn't enough, perhaps reaching this "Eternal I" is more of a personal venture than a collective one as the Dwemer believed. Perhaps it even failed because all of the Dwemeri souls where not sacrificed, there is still one left afterall.
Now Xal states that the souls became Anumidum's metal body, but you ask, why would they do this. Well, this is where the Earthbones that Demnevanni spoke of come into play. Dwemeri metal was no ordinary metal, as Baladas stated, it could defeat time and decay. The Dwemeri souls would become immortal in this state, and at the same time become one to form their god. Kagrenac hit the Heart with the tools during the Battle of Red Mountain and caused this to happen, and the Dwemer disappeared, just as he had intended for them to. But why did the Brass God stay, why wasn't it activated as a god once the Dwemer became one with it. That I do not know. Perhaps it was the Tribunal there that stopped this from occurring, disconnecting the god before it could leave. Perhaps Kagrenac simply didn't see far enough ahead and more than just binding all the Dwemeri souls together to form a god wasn't enough, perhaps reaching this "Eternal I" is more of a personal venture than a collective one as the Dwemer believed. Perhaps it even failed because all of the Dwemeri souls where not sacrificed, there is still one left afterall.
Where in that does it state that it matters whether the Dwemer are alive when their souls were converted into the divine skin? Couldn't their ghosts be converted, I mean a ghost is a soul isn't it?