Chapter 19:
Koto takes her mother from the Shrine's Holy Grounds to the Looking Glass City.
Chapter 20:
The three siblings enjoy their time with their mother, but...
Chapter 21:
Koto tries to find out the secret of her birth from her mother, but instead she's asked to save her poor father.  With no place for her feelings to go, she takes them out on Myoue.
So that's the mother of 
the Council of Three?
Das ist also die Mutter des Triumvirats?
Así que esa es la madre 
del Consejo de los Tres.
Así que esa es la madre 
del Consejo de los Tres.
C’est la mère
du conseil des trois ?
Então essa é a mãe do Conselho dos Três?