Yonah is the daughter of Nier and infected with the ‘Black Scrawl’ virus. Her mother passed away several years ago and she knows her father works hard to provide for her and to find a cure for her illness but wishes he was home more often to keep her company. Even though ill Yonah is exuberant and courageous, trying to lessen her fathers worrying although her attempts usually worsen rather then help.
Yonah is the ‘Replicant’ of a girl from the early 21st century and whose ‘Gestalt’ touched ‘Grimoire Noir’ causing her to relapse. ‘Replicant’ Yonah was kidnapped by the Shadowlord in an attempt to stop ‘Gestalt’ Yonah’s relapse by having her ‘posses’ ‘Replicant’ Yonah’s body. When Nier comes to save his daughter ‘Gestalt’ Yonah willing leaves ‘Replicant’ Yonah’s body telling the Shadowlord "this girl loves her father just as much as I do."