After the battle inside the Ziggurat, Chizuru and Hayate are horrified to find out that their victory would have cost Koyori her life. They agree to help Tazuna and Koyori, even though they're out of the fight now.  They tell the two of them that in order not to be found in the real world, they need to come up with a name to use inside the Ziggurat when they fight.  After a bit of thought, Tazuna and Koyori's new name becomes "Single Gear".
You know, when you hold their hand,
،عندما تُمسِك بيدها
Wenn man die Hände hält,
kann man doch so ungefähr
Cuando se dan la mano pueden saber
Cuando os dais la mano podéis saber
Tu ressens ce que l’autre pense
quand tu tiens sa main.
Ecco, quando vi tenete per mano, quello che
il compagno pensa, i suoi sentimenti e così via,
Sabe, quando seguram as mãos,