Crel the Imp

Enlarge/Reduce.You cause a creature or an object you can see within range to grow larger or smaller for the duration. Choose either a creature or an object that is neither worn nor carried. If the target is unwilling, it can make a Constitution saving throw. On a success, the spell has no effect.

If the target is a creature, everything it is wearing and carrying changes size with it. Any item dropped by an affected creature returns to normal size at once.

Devil's Sight. Magical darknessd impede the imp's darkvision.

Magic Resistance. The imp has advantage on saving throws against spells and other magical effects.

Familiar. The imp can enter into a contract to 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. If its master violates the terms of the contract, the imp can end its service as a familiar, ending the telepathic bond.

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 3) 

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.