Itsuki finds out that in addition to Stardust Labyrinths where the "Impurity Lords" dwell, there is also the 13th labyrinth, as well as the existence of the 13th maiden. He sets out to find the maiden. However, there is the possibility that the 13th is a male. Although not quite convinced, he seeks all the male candidates he could think of...
It's not fair that you've known all along.
.ليس عدلًا أنّكما عرفتما من البداية
War echt mies von euch,
wenn ihr davon wusstet.
No es justo que lo supieran.
No es justo que lo supierais.
C’est pas cool
de m’avoir rien dit.
Non è giusto, eravate al corrente di tutto!
Não vale se já sabiam de tudo.
Как-то нечестно, 
что вы обо всём знали.