Echo

The only reason I.M.P could go to the mortal realm and kill people for a living is thanks to a unique little Imp named Echo.

With her friendly personality, kind and loving aura, creative mind, and secretive badass skills, Echo was able to convince one of the most influential royal demons of Hell named Prince Stolas to use a magical book called Grimoire to help her with her older brother, Blitzo's business.