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Tiny fiend (devil, shapechanger), lawful evil
Skills Deception +4, Insight +3, Persuasion +4, Stealth +5
Shapechanger. The imp can use its action to polymorph into a beast form that resembles a rat (speed 20 ft.), a raven (20 ft., fly 60 ft.), or a spider (20 ft., climb 20 ft.), or back into its true form. Its statistics are the same in each form, except for the speed changes noted. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.
Devil's Sight. Magical darkness doesn't impede the imp's darkvision.
Magic Resistance. The imp has advantage on saving throws against spells and other magical effects.
Sting (Bite in Beast Form). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) piercing damage, and the target must make on a DC 11 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one.
Imps are found throughout the Lower Planes, either running errands for their infernal masters, spying on rivals, or misleading and waylaying mortals. An imp will proudly serve an evil master of any kind, but it can't be relied on to carry out tasks with any speed or efficiency.
Variant: Imp Familiar
Imps can be found in the service to mortal spellcasters, acting as advisors, spies, and familiars. An imp urges its master to acts of evil, knowing the mortal's soul is a prize the imp might ultimately claim. Imps display an unusual loyalty to their masters, and an imp can be quite dangerous if its master is threatened. Some such imps have the following trait.