Imp
Tiny Fiend (devil), lawful evil
200 XP
Special Abilities
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.
Variant: Familiar
The imp can serve another creature as a familiar, forming a telepathic bond with its willing master. While the two are bonded, the master can sense what the imp senses as long as they are within 1 mile of each other. While the imp is within 10 feet of its master, the master shares the imp's Magic Resistance trait. At any time and for any reason, the imp can end its service as a familiar, ending the telepathic bond.
Actions
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.
Invisibility
The imp magically turns invisible until it attacks, or until its concentration ends (as if concentrating on a spell). Any equipment the imp wears or carries is invisible with it.
Quick Reference
Running This Encounter
Imps are best used as minions, messengers, or scouts for a larger evil force rather than standalone threats. Use their invisibility and shapechanging to create surprise and confusion before combat begins. They excel at hit-and-run tactics, poisoning supplies, or stealing objects rather than direct confrontation. Consider having them flee when heavily damaged, as they serve larger masters.
Combat Tactics
Imps use invisibility to gain advantage on attacks, favoring their poisonous sting to wear down enemies over time. They avoid direct melee combat with multiple opponents, instead striking from hiding and retreating to reposition.
Environment & Setting
Imps thrive in dungeons, towers, and infernal chambers where they can use tight spaces and verticality to their advantage. They are often found as servants in the lairs of warlocks, devils, or other powerful fiends.