Shinmai Ossan Bouken-sha, Saikyou Party ni Shinu Hodo Kitaerarete Muteki ni Naru.

It is common knowledge that it is best to become an adventurer while you are young. This is because the "magical power" that is the basis of an adventurer's strength can only be developed if the adventurer trains while young. But this newbie adventurer, Rick Gladiator, who only became an adventurer