What happened to the imp?

I love imps they are funny, clumsy, cute, when they appear in folk stories you know that some funny mischief will happen. They are funny, and though they provide a conflict they are safe like Tom, or Sylvester, or the coyote who can not catch the road runner. One thing I could not understand is where did they go? If Latvian, Russian, some Germanic and Scandinavian folk stories are  stuffed with imps the British ones seem to substitute the word 'imp' for 'devil' or 'demon'. In art imps are also none existent there are a couple of small black imps in earlier manuscripts but that is about all.  The only imp I am aware of in Britain is the one hiding on one of the columns of Lincoln Cathedral. 

So what happened to the imp? Today I came across one plausible explanation - Theater. Let me explain. Obviously different art form influence each other. Literature, art, music, performance all have an effect on each other. For example it is believed that the 13th century ceiling mosaic of Florence Baptistery greatly contributed to the image of hell in Dante's Divine Comedy.

The punishments of the damned. Detail of Last Judgment scene in the Byzantine-style ceiling mosaic, 13th century. Florence Baptistery, Florence, Italy.

According to  J.B. Russell (in 'Lucifer' my current bedside book) it was hard to represent the little black imp on stage and even then it lacked horror and looked unimpressive. The desire to impress audience encouraged a more grotesque representation of the Devil in theater which then migrated in to visual representation. With that the representation of the little black imp declined by late medieval ages and was completely substituted by more grotesque images.