True followers or devotees of Ielitha Dema are probably fairly rare, but I could see a lot of types of people asking her for her blessing, as it were. Spies, curators, artists, explorers... anybody dealing with secrets or curiosities. She might also be popular among executioners, thus "the Hangman's Lady".

Those cults that do exist purely to serve her would be very mysterious and secretive and probably quite small.