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.