Tailors are Grisha of the Corporalki order. They have the ability to change a person's appearance. Tailors were once considered rare and special; however, in Ravka, tailoring is now taught to all Corporalki students of the Second Army. Genya Safin was the first known Tailor and was considered a low-level Grisha who served the Queen of Ravka before the Ravkan Civil War. In the Second Army they wear red kefta with blue embroidery.
Tailors can change a person's eyes and hair if they have the right material, or take away or give a tattoo. A primary example of tailoring is Sturmhond, as he was tailored to have red hair, green eyes, and a crooked nose when in fact he has blonde hair, hazel eyes and just a small bump on his nose.
When a Corporalki on jurda parem uses their ability to tailor, the changes made to a person are extremely skilled and borderline permanent. In the case of Wylan Van Eck, who was tailored to look like Kuwei Yul-Bo, the only person able to change him back to his original face was Genya Safin.