Shinmai Ossan Boukensha, Saikyou Party ni Shinu hodo Kitaerarete Muteki ni Naru.

Rick Gladiator spent most of his youth working behind a guild counter, then decided after turning 30 to pursue the adventuring career everyone assumed he had started far too late. His instructors, however, were the members of Orichalcum Fist, one of the strongest parties in the world, and their idea of training for two years bordered on attempted murder. When Rick finally appears for the lowest-rank examinations, younger adventurers see an older rookie with an unimpressive classification and immediately underestimate him. They have no idea that his body, reflexes, and strength were forged to survive opponents far beyond beginner level. For Rick, the hardest part of starting late may simply be convincing everyone that he is nowhere near as inexperienced as he looks.