Last Round Arthurs, Vol. 4 (light novel)

THE SEARCH FOR THE IMPOSSIBLEEver since Rintarou awakened the power within him, he’s felt largely at peace with himself … even though most of his days are still spent trying to keep up with Luna’s reckless antics. When he realizes his new life has come at the cost of Nayuki’s, though, he just can’t accept her sacrifice…or fully process the loss of his friend. The only way to save Nayuki is to obtain the Holy Grail, an object that has eluded seekers since ancient times.

Even before embarking on a quest for the unattainable chalice, Rintarou has a feeling he might be out of his depth…