That imp is just a lousy imp. No, he does not have any fantastic physical powers. As a mage, V is not likely to be much of a physical powerhouse either, but she can still likely take the imp without using his spells.
The imp's danger is from temptation. He may be able to offer V what she very much wants. He is not going to have to attack him.
Haley at this point in comic time is just meeting the cleric, and has yet to recover Roy, or deal with her old friend.