River sloth is robbing your bags...

A family or clan of strange goblin-like creatures roam a shaded and forested stretch of the Ne-Ban River, in the southern reaches of the Empire, where jungle takes over from temperate forest.  This stretch would be little travelled, if it were not for constant rumours of the Golden Treasures of the Third Dynasty of the Kyghan secreted somewhere in the eroding spires and citadels clustered above the vast waterfalls named The Tears of the Princess Almesha (by the Imperial Loyalists) and Dead Hag Falls by all others.  These falls are only reachable by boat up the Ne-Ban, as no roads cut through the thick, boggy growth for at least fifty kilometres in any direction.

Every decade or so the chance find of a jewelled diadem or platinum pectoral amongst the dangerously narrow, rubble filled galleries or walkways that are constantly washed by the spray of the waterfalls, sets off another rush of Imperial Tax Collectors, treasure seekers, mages (for what reasons, only they know) and other scoundrels of the Empire and surrounding Realms.

Although they do not know it, as they rent, hire, buy or steal boats and barges, and use slaves, hired sailors or strange magics to speed them upriver against the changeable currents, their most dangerous challenge (at least, from a financial viewpoint) comes even before they hear the falls.

After they pass several days of boulder-strewn rapids in a deep, narrow canyon, boats reach a secluded section of river.  Here, most parties rest in exhaustion, at least, those that didn't drown, get crushed under shifting house-sized boulders or trapped in the nets of the water fey.  Usually at night, but sooner if all are sleeping or distracted, the inhabitants of these waters slowly and quietly slip on board and head straight for the luggage.

Using razor sharp claws, they slice and slit packs and bags, seemingly searching exclusively for ornaments, jewellery and potions, which they drink, adorn themselves, or attempt to wear, as the case may be.  If discovered, they dive over the edge and swim away to their beaver-like underwater lodge, or, if unable to, can strike out with their razor sharp claws.

If spoken to, they seem to understand simple common, although they do not speak. They gesture accordingly, and can be bargained with, taking potions, especially those of healing or effective against poison or disease, in exchange for either items stolen and worn (usually from the bargainer) or simple directions to the network of caves that give access to the Upper Falls.

If tolerated or dealt with non-violently (or destructively, given the use of base magics amongst these sorts of travellers) the Ne-Ban Goblins are a comic annoyance.  If harmed, however, they can make the life of intruders into their waters very difficult, puncturing boats, stealing weapons and magical implements, and their nimbleness and inherent magic resistance assists with this.

 The true reason for the need for healing magics is the (natural) poor health of their young, who do not grow fur or learn to swim until their 5th year, leaving them subject to many of the pests and diseases of the lodge.