The Abyss
The Abyss is a yawning, impassible gorge between Loamhedge Abbey and the rest of the Southern Plateau that was created due to earthquakes. It is unknown how deep it is. At one point in time, some creatures managed to construct a bridge that was hung low into the abyss. During the time of Mattimeo, after Slagar the Cruel and his captives crossed the abyss to get to Malkariss, Slagar then burned the bridge so that Matthias and his companions could not follow him. The last bridge was lost, leaving it impassible for all those without wings. With the help of Sir Harry the Muse, the woodlanders recovered the remains of the bridge, then used their belts as a zip line to get across.
When Malkariss' kingdom collapsed, its inhabitants were thought to have been crushed in the cataclysmic event. In Loamhedge, however, it appeared that some of the deeper tunnels remained and were ruled by Kharanjul and his horde. These tunnels opened out into the gorge where the Lord of Mossflower had fallen and was used as a new bridge. This was called 'The Abyss' by Kharanjul's followers. These vermin were vanquished in the Battle in the Abyss, and the Lord of Mossflower fell inside.