Kill Taran and his henchmen quest

Thenedor

The description of this quest implies that you need the Sword of Divine Lightning to kill Taran and his henchmen, but I managed to kill Storm without having it (have not encountered the others yet). Is this a bug or do you only need it for Taran? (I am playing the Android version which I enabled in the main game if that matters.)

Thanks.

Catacomber

You only need it to kill Taran.