: Eighty years ago, Frieren's original hero party could not defeat Qual. He had developed a revolutionary spell called Zoltraak —"Killing Magic"—which bypassed all contemporary human defensive magic and gear. Lacking a way to block it, the party chose to seal him away instead.
: Frieren informs the demon that his "killing magic" is now considered a basic spell for novice mages. Frieren and Fern then use the modernized version of his own spell to destroy him. Core Themes : Eighty years ago, Frieren's original hero party
The story highlights the and the advancement of human knowledge . While Qual remained frozen in time, humanity spent eighty years analyzing and overcoming the greatest threat of the previous era, turning a legendary terror into a textbook exercise. : Eighty years ago