|Appears in||Words of Radiance|
Iyatil is a short, tan-skinned woman who wears a carapace mask tied to her face.
|“||The arrangement of red-orange carapace pieces was like a mosaic, giving a hint of eyebrows, of anger and rage.||”|
Behind the mask, she has unblinking dark eyes and an impassive mouth. She wears simple, dark brown clothing tied with an intricate belt, studded with more carapace.
Iyatil is very self-contained, revealing little about herself, until she encounters Shallan. She professes to Shallan to be Mraize's master (instead of the other way around, which Shallan has assumed, based on her previous encounters with Mraize).
|“||He is not my master. He is my student.||”|
Another of these three places is Scadriel: in Shadows of Self, there's a story in one of the broadsheets about someone seeing a woman with a scary mask emerging from a pool of water in the mountains. This is likely Iyatil, returning from Roshar.
Lastly, there is a place – yet not a world – in the cosmere where a lot of Worldhoppers have settled; it is where Iyatil is from, even though her ethnicity is not from there. This place is Silverlight, and Iyatil is a Malwish Southerner – a Hunter? – though she was not born on Scadriel. She wears a mask; it might grow into her face, just as do those of the Hunters. And, just as the Malwish feel about Northerners on Scadriel, Iyatil has the following exchange with Shallan (again, as Veil):
|“|| "Why the mask?" Shallan asked. "What does it mean? Why do you hide?"
"I have many times asked," Iyatil said, "why those of you here go about so brazenly with features exposed to all who would see them. My mask reserves my self. Besides, it gives me the ability to adapt." 
Since Iyatil is not a native of Roshar and uses carapace to disguise herself while there, she may have knowledge of the Parshendi, though to what extent remains unknown.
In addition to her abilities as a Worldhopper, Iyatil is also an assassin. She attacks Amaram with her blow darts during his attempt to remove Taln from Dalinar's temple complex. Taln saves Amaram's life by snatching the darts out of the air. Iyatil was attempting to kill Amaram because his maps and possible attempts to find lost Urithiru appear to be in conflict with the plans of the Ghostbloods.