The Strongest Sword Saint with Maxed-Out Defense

Eugene was born into a renowned family of swordsmen. Though he possesses unrivaled defensive ability, he has no offensive power at all and has been branded a “defective swordsman.” He decides to leave his homeland and enroll at the continent's top institution, the Academy of Magic. While he is there, the prison sealing away restless mythical creatures comes under threat. As the only person unaffected by its miasma, Eugene is sent to its deepest level. Even battle-hardened archmages can only make it halfway before collapsing to their knees. At the prison's deepest point lies the sealed legendary Demon King Eline, who once ruled the continent. Eugene reaches her with ease, and seems to be the only one who can form a contract with the Demon King...!? This is an otherworldly fantasy about a failed swordsman who wields the Demon King's power and becomes the strongest Sword Saint!