Yna is a prostitute at the Happy Port brothel in Braavos.
Yna has one eye and is a maegi, who can tell the future from tasting a drop of blood. Arya Stark considers the prostitutes of the Happy Port to be nice people, including Yna.
Yna goes over to Samwell Tarly when he enters the Happy Port, throwing her arm around his neck and pressing her breasts against his chest.
When Cat of the Canals visits the Happy Port, Yna is braiding Lanna's hair.
Prior to the performance of The Bloody Hand at the Gate, Mercy takes a quick peek out into the house and sees Cossomo the Conjurer with Yna on his arm in the pit.