Kira seems to know who Hinako really is, and wants her to give up her conquest of the school. It seems the only way for her to convince him otherwise is to fight him... and win.
And anyone who picks on 
my sister is gonna pay!
!وأيًّا يتنمّر على أختي فلن أسامحه
Und jeder, der meine
Schwester ärgert, kriegt aufs Maul!
¡No dejaré que nadie la moleste!
¡No permitiré que os metáis con ella!
Ceux qui l’emmerdent
auront affaire à moi !
E tutti quelli che fanno del male 
alla mia sorellina la pagheranno!
E quem mexer com a minha irmã
 vai se ver comigo!
Будете приставать к моей сестрёнке, 
получите от меня!