If we're talking about Lizardmen stuff, the 7th edition also says some stuff. Page 7.
"Even as the gateways collapsed, the Old Ones departed from the world. Whether they were destroyed or they simply abandoned the world to its fate, none will ever know. The Old Ones were beings of order and life, and Chaos was anathema to them. The raw stuff of Chaos coalesced into solid form, to rain down upon the world, poisoning life and bringing into being all manner of twisted and unnatural creatures. At the poles, great chunks of the stuff fell to earth, the remnants perhaps of the gateways themselves. Further afield smaller rocks plummeted through the sky upon wierdling contrails, setting the air afire with pulsating, eerie lights. No region escaped, as a fine layer of warps tone dust settled across the entire world, bringing mutation to all. Where the gateway had once been, now there throbbed a second moon, a malevolent, green satellite made from the very stuff of Chaos."
*raw stuff of Chaos in solid form, rained down upon the world
*big chunks of Chaos-stuff fell down at the poles, maybe the gateways themselves?
*lots of meteors flew through the air
No real hint-hint-wink-wink type stuff about star-metal and gromril in there.
Another few interesting things I found in 7th edition was this bit. Page 6.
"Upon the plains of the world the Old Ones encountered the primitive creatures that would one day be taken up and transformed into the very first Elves, Dwarfs and Men."
So Elves, Dwarfs and Men existed before the coming of the Old Ones and weren't just a purely Old One creation. That's actually interesting because the common refrain nowadays in every thread is that it's Dragons, Dragon Ogres (and sometimes Sky Titans IIRC) that were the original leftover inhabitants that still persist to this day, and that Elves, Humans and Dwarfs were Old One creations. And apparently the Elves were taught their magic at the lap of the Old Ones/Lizardmen, whereas the Dwarfs had innate and intrinsic magic...
"The first created were the Elves, who learned the lore of magic in the lap of the gods, followed by the Dwarfs, whose magic was not learned, but intrinsic and instinctual."
So the Dwarfs had runic magic all along? Maybe it was something to do with their origin myth, or with the Ancestors themselves, or maybe the Ancestors were just the ones that figured out how to use it... Still, this implies interesting stuff about the creation myths of the Dwarfs. Did they have magic even before the Old Ones came? If so, their Ancestors might be even older than thought of before... Eh. Who knows.
Also, apparently the world used to be a mega-continent. It used to only have a thin band in the middle that could sustain life though, so it wasn't all frozen planet, interestingly enough...
"Many aeons ago, the world was a cold, dark and windswept place. Ice sheets covered much of the surface, a thin equatorial band the only region capable of sustaining much in the way of life. Savages roamed the land, battling the elements and other, more ancient and evil things, for survival. Who knows what inhuman civilisations rose and fell in that forgotten age, their remains now buried by the passage of time."
"The next stage of the Old Ones' plan was the realignment of the tectonic plates. From the single mega-continent revealed by the retreat of the ice sheets, the Old Ones set into motion a plan that would see the formation of entirely new lands and seas, making the world conform to an established pattern compatible with their ends. This realignment would take many millennia, none other than the Old Ones knowing its final form or purpose."
