Imp
Source: Monster Manual (2024) p. 177, Player’s Handbook (2024) p. 352, FRHoF. Available in the SRD and the Free Rules (2024)

Imp
Devil of Pettiness and Suspicion
- Habitat. Any
- Treasure. None
Known for their cowardice and toadying, imps serve devils and wicked magic-users. Their abilities to shape-shift and pass unseen make them skillful spies and adept at fleeing danger. Imps sent to surveil other creatures relate what they discover to their masters, but they frequently omit important details or cast events in the worst possible light to mislead their masters into following the imps’ devilish council.
Imps without masters delight in manipulating other creatures and inflating their own egos. They might take over bands of weaker monsters, or they might pose as helpful spirits and trick influential individuals into pursuing nefarious ends.
A quote from Skeever, Imp Servant of Firan Zal'Honan
I can tell you what I know, but wouldn’t you rather I tell you what’ll let you do what you know you’re going to do anyway?