An Illiomancer is a type of magic practitioner in the Briarverse.
Illiomancy is a type of magiq, seemingly related to the artistic field of illustration. Bernard Sleigh and Helen Wilde were both illiomancers, according to Sullivan Green.
The term illiomancer appeared in Sullivan Green’s Monarch Papers, Volume 3. It was used to solve Fragment Six, which described an unknown illiomancer named Bernard Sleigh, whose Map of Fairyland contained locations needed to find the word Galluskulk.