Katainaka no Ossan, Kensei ni Naru Gaiden Ryuu Soken no Kiseki

Serena, a Platinum-ranked adventurer, once trained under the legendary Beryl. One day, she takes on a routine goblin extermination request in a remote village. However, the request comes with an unusual condition—she must train a young girl, Nell, to become a proper adventurer. Nell, inexperienced and unable to defeat even a single goblin, dreams of becoming an adventurer for a reason she refuses to share. Though initially hesitant, Serena sees a spark in the young girl and takes her under her wing. As Nell struggles to grow stronger, Serena herself continues her journey, overcoming countless battles and challenges. This is the story of Serena’s rise to the peak of the adventurer ranks—Black Rank, and the bonds she forms along the way.