: Aside from the map, the only info we have is in GURPS,
: which says: "One of the greatest mysterious of
: Myth is the Drowned Kingdom. More than 2,000 years ago
: Yer-Ks was a vigorous human state, famous for its
: powerful sorcerers, mighty knights and fearless
: seafaring. For reasons unknown a cataclysm
: occurred--the sea rushed in and flooded the once-great
: nation.
: Vast ruins now slumber beneath the waves of the northern
: ocean. To date, those mages with the magic to reach
: them have shied away from the kingdom's dark legend.
: Whispered tales say that Yer-Ks obtained a power that
: threatend the Trow--and the powerful Trow used a
: fragment of Callieach magic in retribution. Other
: versions attribute the same motive to the dark gods
: themselves.
: Fishermen and sailors swear that the waters over Yer-Ks
: are always rougher than those to north, west, or
: east."
: It also says in the section on the Deep Mire: "This
: salty march is home to the Skrael, an amphibious race
: long subject to the Yer-Ks...they have long since
: given up living in the ocean (though they still patrol
: the region of Yer-Ks) and make their villages in Deep
: Mire...it is believed they would defend Yer-Ks as
: their own property as well."
Hrm! The Skrael were subject to the Yer-Ks, and then the Yer-Ks were suddenly drowned! Maybe the Skrael did it!
On second though, nah. It was definitely the Callieach, working through the Great Devoid to command Spiders to aid the Dwarves, pissing off the Ghols and thus their slave-masters the Trow, and inciting them to KIK their nearest neighbors, the Yer-Ks ;-)