The double-headed demon has been stuck with magic powerful enough to fell a dragon. In the aftermath, Morlock feels sympathy for the demon dog and says he wants to try to save it. But then, Saitou and the others are struck by a surprise attack!
I swear to repay this 
debt of gratitude one day.
أقسم بأن أردّ هذا الدين يوماً ما
Ich werde mich für dieses
großzügige Geschenk erkenntlich zeigen.
Juro pagar esta deuda algún día.
Juro pagar esta deuda algún día.
Je te revaudrai ça, juré.
Prometto che un giorno ripagherò questo debito.
Prometo pagar essa dívida 
de gratidão um dia.
Однажды я отплачу свой долг.