The Giant's Teeth are perhaps the least hospitable terrain in the entire Border Princes (though those who live by the Pale Waste might disagree.) An expanse of rocky, wind swept hills with little in the way of life other than snakes and scorpions.
The sheer undesirability of the Giants Teeth is that in an area that generations of princes would gleefully murder each other for a few acres of scrubland the hills are practically barren of ruins.
According to legend the Giants Teeth were once even more fertile than the High Pastures and home to a race of giants akin to those of Albion. A powerful warlock cursed their land, turning the rolling hills arid and the giants starved to death (and not before turning on each other.)
No one knows the truth of this... but then no one has ever cared enough to investigate.