Failure Frame: I Became the Strongest and Annihilated Everything With Low-Level Spells (Light Novel) Vol. 6

In search of the Country at the End of the Word and its secrets of forbidden magic, Mimori Touka plunges back into the Land of the Golden-Eyed Monsters. But on the way he's confronted by perilous new foes: the descendants of previous heroes from another world! The E-class underdog must flex his 'useless' skills in a battle against their Sword of Courage and leader, the indominable Lewin Seale.