Well now you've given me ideas for the Cause of the Mourning.

Cyre was a nation that loved the arts, including music. Suppose they decided to research and modernize Dhakaani magic through Cyrean music? Where did they get the idea? Let's suppose there were Dhakaani ruins in Cyre, say under the location of a Genesis Forge. They also found evidence of ancient forges running on geothermal power, and decided to build their own forges there, including a Creation Forge.

Then some researcher stumbles on the dream magic. It has limited success because you can't get test subjects to dream about the same thing, no matter how much training and prompting given in advance. But, someone has the bright idea - what if we teach warforged to dream? They do as ordered, so let's get a group of them to dream the same thing. Playing music is known from the previous dream research to aiding people to dream, so apply that to.

Things go well. The dreaming warforged, made from the primal energies of the Creation Forge, aided by Dhakaani music magic, prove capable of inspiring successes - instantaneous transmission of shared ideas - battle tactics, maps, awareness of enemy movement; "singing" (reproducing particular music-enhanced magic sung to them) to troops in different locations. The military of Cyre could operate like none since the Dhakaani Empire.

Top brass don't want to wait for scaling up field tests. It works well in controlled lab conditions and hidden military test sites. Don't tip off the enemy with more testing. So they install dreaming warforged across the country, on every front, along the entire border. The evening before, the dreaming warforged are given their instructions about what to dream - the map of Cyre, enemy positions, all possible tactics that can be used, and the grandiose idea of turning Cyre into the most terrifying power on the continent - and are sung to sleep. The musicians are told to make this their best performance yet, really enhance what the warforged dream.

All of the possibilities, enhanced by bardic magic, fed into the shared mindscape of the dreaming warforged, lets them access Dal Quor. It turns into a bad MidJourney/AI experiment. So many minds, so much input and possibilities, magically enhanced, in Dal Quor... the dream becomes a confusing nightmare of potentiality, envisioned by minds that have hardly any sense of reality constraints. The Mourning is unleashed.

Did the dreaming warforged wake up, or are they still dreaming the Mourning?