Nico

ニコ
She is the main character in her own picture book in her picture book she always smiles no matter what however the Demon King took her ability to smile away from her and trapped her within a castle. However the story thus ends like that since the last few pages of the picture book were ripped apart. Miyuki reading the picture book promises Nico that she will draw the last few pages for her but never did which soon made Nico hate her.