Gimmerlings are small, shapeshifting fey who stage ambushes to sate their endless hunger and childish greed. These cruelly curious fey obsess over finding and making unusual traps and sadistic weapons, and their favorite amusement is seeing these traps sprung or the weapons wielded. When on the Material Plane, they are frequently found in urban areas, particularly slums or other parts of town where they can either go unnoticed or be easily forgotten—and have plenty of victims to choose from.

A typical gimmerling disguises itself as an endangered child, doing so in hopes of drawing creatures close enough to rob. The gimmerling puts itself in apparent danger using a trap, construct, or bribed ally, or even a coerced monster like a redcap.

Because gimmerlings sometimes trade obscure smithing or trapping techniques in exchange for gifts that sate their curiosity, their greed, or their hunger, they have at times been worshipped as minor gods of the forge. Some disciplined gimmerlings work as honored artisans, elite guards, or spies for demigods.