Re. the Burn, there's some previous lore set up in the Azim Steppe - I posted about it in the 4.3 discussion thread and I'll copy-paste it here:


The cave-dwelling Uyagir in the Nhaama desert (cave entrance at X:8.8, Y:29.6) seem to claim their ancestors were responsible for what happened.

Baavgai explains:
We live here to make amends for our sins. In the past, having grown drunk off its own greed, our tribe embarked on a mission to subjugate all that it possibly could.
In response to our insatiable greed, the gods punished the Uyagir by unleashing giant, oliphant-like beetles upon our lands.
The beetles left absolute devastation in their wake. Rivers dried up, crops wilted and cavernous holes were dug in the southern deserts.
Our ancestors, faced with the result of their avarice, swore to repent for their mistakes. They chose to live in the caves bored by the giant insects and abandon all greed.
So... did they summon a primal to defeat their enemies? Were the beetles some kind of primal gone out of control or even someone else's primal? (something on the scale and behaviour of Bismarck I suppose.) Or even Allagan bio-warfare or machinery as perceived by a primitive tribe?

It's a little ambiguous whether they are currently living in the bored caves though, or if they moved out into different caves later. But the world map does have a drawing of a giant worm (beetle larva) in the Burn, so that part seems to add up.


They also have cave murals that, according to one of the other tribesmen, "tell stories of our ancestors' greed":

(I only took the one screenshot and forgot to check the other cave walls to see if they had different images. This one doesn't seem particularly useful in the end.)

All on the right seem to be hunters and horses, directly behind the scaffolding are mammoths (?) and at the top is a warrior with a sword riding possibly-a-yol.

I'm not certain but I think this might be the same mural in the cave where you fight the yol at the end of Bardam's Mettle. Whether that would mean anything or if they just recycled the design.


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And now here we are, seeing more of the Burn 'for real', and it has giant worm carcasses scattered across it. Whatever happened, it was something more solid than "just" a primal, and perhaps the worm-tunnels are still there waiting to be explored.

For that matter, perhaps some of the worms are still there.