Deleted post
This is what it says:
Imps have also been described as being “bound” or contained in some sort of object such as a sword or crystal ball. In other cases imps were simply kept in a certain object and summoned only when their masters had need of them. Some even had the ability to grant their owner's wishes much like a genie. This was the object of the 1891 story The Bottle Imp by Robert Louis Stevenson, which told of an imp contained in a bottle that would grant the owner their every wish
Basically what it boils down to is that if Ily wanted to, she could trap and bind Kym to some sort of object, and Kym would HAVE to obey her.