After low-ranking adventurer Rentt is eaten by a dragon, he regains consciousness and discovers he has undergone a surprising transformation.
Having evolved into a ghoul, Rentt continues fighting monsters. He sees a novice adventurer being attacked by a skeleton and decides to help her.
Rentt turns to his friend Lorraine, who is a student of magic, for help with his predicament. He later visits a blacksmith and asks for a new sword.
Rentt cuts his exploration short and brings the grateful adventurer back to town. All the while, he struggles with a craving for human flesh.
Now a more humanlike thrall, Rentt wants to take requests at the guild. Worried he'll stand out, Lorraine suggests he register as a different person.
After Rentt impresses the guild, he is invited to take an exam to reach the next rank. He and two other hopefuls team up and venture into a labyrinth.
Thanks to Rentt's experience, he, Raiz and Lola successfully make it through the labyrinth. Later, Sheila confronts Rentt about his true identity.
Rentt tests out an impressive new sword made for him by the blacksmith Clope. Afterward, Rentt encounters a troubled villager who asks him for help.
A curious Rentt accepts a low-paying quest from a young girl who needs a rare medicinal ingredient to cure the ailing manager of her orphanage.
Rentt meets someone else tasked with gathering the blossoms. After delivering the flowers to Alize, he suggests that she learn magic from Lorraine.
While Rentt continues through the maze in search of the Latuule family mansion, he stops and drinks tea with a young girl, who offers to buy his mask.
Rentt resolves to drink the vampire blood. When Lorraine asks him why he wants to attain mithril rank, he begins telling her about his past.