Even Given the Worthless “Appraiser” Class, I'm Actually the Strongest, Volume 15

Hounded by regret after hurting Yuri’s feelings, Ein finally accepts his own feelings for her. But just as he does, Theresia, the ninth of the spirit sisters, appears before Ein. Convinced that Ein is Miktoran, Theresia uses her Demonic Oath Eye to erase Ein’s memories. To make matters worse, the demons choose that moment to make their attack. In the darkest hour, Yuri steps forward to rescue Ein!