Lowfolk generally lack magickal power, though anecdotal evidence indicates that some of them are capable of learning magick. Lowfolk have tragically short life spans as well, but are compensated for their shortcomings by possessing great physical strength & vigor as well as high fertility rates.
Elves in the Long Ago used to enjoy playing pranks on lowfolk (still approved as an honorable and Elfly pastime), and seducing lowfolk into venery - which is now generally frowned on. Late-era Imperial elves are somewhat afraid of lowfolk because in the ancient ballads which tell of elf / lowfolk encounters, the elf is usually outwitted, and often killed.
Despite this superstitious dread, it is still customary for elves to secretly exchange their babies for lowfolk babies. The elf child left with lowfolk foster-parents is called a changeling. The stolen lowfolk baby, which is taken to Faerie, is called a swapling.