kono-yaku-tatazu-zatch-bell.png

Translation

• kono
  yaku tatazu ga!!!
  この役立たずが！！！
  [You useless brat]!!!
  • yaku ni tatsu 役に立つ
    To be useful.
    To act [one's] role. (more literally.)
  • tatazu 立たず
    Zu ず form of tatsu 立つ.
    Without doing (whatever tatsu means in the context.)
  • yaku tatazu 役立たず
    To be useless.
    Without acting [one's] role. (i.e. unfit for the job you were given.)
  • ga が particle
    This marks the subject, it's untranslatable.
    Normally it comes before something else, but the phrase is cut short here.