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...
I thought maybe I should learn a 
bit more about the thirteenth labyrinth.
.ارتأيت أن أتعلّم أكثر بشأن المتاهة الثّالثة عشر
Ich dachte, ich sollte vielleicht etwas mehr
über den 13. Dungeon in Erfahrung bringen.
Pensé que podría saber más
del decimotercer laberinto.
Pensé que podría saber más
del decimotercer laberinto.
Je me disais qu’il me fallait
en apprendre plus sur ce 13e labyrinthe.
Ho pensato fosse meglio
saperne un po' di più sul tredicesimo Labirinto.
Achei que precisava saber mais
sobre o 13º labirinto.
Я подумал, что нужно побольше узнать 
о тринадцатом уровне лабиринта.