Droki

Attentive characters can spot a curious figure darting between the stalls and shops of the Blade Bazaar. Every time they roam the market, they have a 20 percent chance to see a derro dressed in rags styled as an imitation of a fancy jacket, wearing a wide-brimmed hat with two tentacles from a displacer beast sewn into the hat's crown. A large satchel hangs from his shoulder, and he's always muttering to himself.
Duergar merchants glare scornfully at this derro, and none will discuss him with the party. Investigations can find that this figure is named "Droki" and he serves as a courier and supplier of goods who works for disreputable employers.


Source: Out of the Abyss Pre-Made Adventure