Yuuto's been sent to another world, where he is now commander, or "Patriarch" of a clan of warriors.  To survive in this new world, he uses his cell phone, his only connection to the girl he loves back home.
It's a holy ritual called
the Oath of Allegiance
Es ist ein heiliges Ritual, das man als
„Loyalitätseid“ bezeichnet.
Un ritual sagrado,
el juramento de la alianza,
Un ritual sagrado,
el juramento de la alianza,
Un rituel sacré nommé
« le serment de la coupe »
È un rituale sacro chiamato 
Giuramento di Fedeltà,
É um ritual sagrado chamado
de Juras de Lealdade
Это священный ритуал 
под названием Клятва Верности,