What is the origin of imp?

Imp “a little devil or demon” derives from Old English impa “shoot, graft,” via Latin impotus from Ancient Greek émphytos “planted, implanted.” This Ancient Greek source is related to the noun phytón “plant,” which is the source of the English combining forms phyto- (as in phytochemical, a compound found in plants) and -phyte (as in neophyte “a beginner or novice,” literally “a new plant”). The story of how a word for “plant” became a word for “little devil” is less complicated than one might think; from “plant,” the definition shifted to “offshoot of a plant,” and from there, it broadened to include any offspring, plant or animal. The phrase imp of the devil, meaning “offspring of the devil,” gave imp the additional sense of “demon,” which the word has preserved to the present day though it no longer appears in that phrase. Imp was first recorded in English before the 8th century.