The Grimly Wood was once Troll country, but after the coming of Golo the Tyrant, the Trolls migrated northward to Murbletoad Marsh. There, the great majority of their kind built bridges over the many waterways and became very industrious as Tally Taxers. However, during their reign over Grimly Wood, the Trolls definitely made a lasting impression for future generations to remember them by. To stake their claim, bands of Trolls would often mark their territory by leaving behind piles of dung on the forest floor. And in many cases, these piles have remained for hundreds of years, now petrified by the sun.
Modern Trolls are not so uncouth; in fact, they can be quite civilized, and for the most part possess an understated humility and practicality that is not unlike other human folk. But their dung is still quite the prize among the initiated. Petrified Troll dung is a sturdy material, both waterproof and insusceptible to fire–which makes it ideal for building. (Trolls themselves are privy to this and have utilized their own waste as a building material, until the practice became unfashionable and “revolting” to the modern, more sensitized Trolls of the Dungeon Era.)
But it is the Boggles–the inimitable turd-burglars of the ecosystem–who immediately overtook and converted the remains of the Grimly Wood Trolls into their dwellings, just as they have wormed their way into every hollow log and snarl of roots. In every dollop of hearty Troll dung, you can be sure there is a quaint Boggle family, drinking mud tea out of mouse skulls.