As daughter of the former demon lord, Mio's foster parents were slain by powerful demons after her life. Still seeking to slay her, Basara reveals himself as a member of the hero clan--an enemy of the demons--and vows to protect Mio as a member of his family.
So when the subordinate takes 
rebellious or traitorous actions,
Sollte der Untergebene also rebellisch
oder verräterisch agieren,
Cuando el siervo se pone rebelde
 o hace un acto de traición,
Cuando el siervo se pone rebelde
 o hace un acto de traición,
Donc le maléfice s’active
lorsqu’ils se révoltent
Per cui quando il subordinato agisce
 in modo ribelle o da traditore,
Então quando o Servo trai
 ou desobedece o Mestre,
Поэтому когда слуга бунтует или предает, 
активируется проклятие.