Imps and Gremlins (the two terms are interchangeable) are minor daedra, often appearing as wizened little grey-skinned creatures with shining blue eyes and a mischievous grin. Imps may perform small magical favors or grant wishes, but they are much like leprechauns in the sense that these "favors" are often twisted to the imp's own amusement. Some of them find work as advisors and research assistants to wizards, though such creatures are always trying to twist their human "masters" into becoming slaves to the daedra lords.
An imp that shows exceptional prowess and cunning can be promoted into a more powerful form of daedra — usually a wraith, occasionally a balrog, incubus or succubus. Imps themselves have no discernible gender, so their assignment to become male or female in these more powerful forms is apparently random (though it may be based on personality).