The World's Strongest Rearguard

Arihito sets out to his first dungeon after waking up in Labyrinth Kingdom. Theresia, a lizard man mercenary, accompanies him on his exploration.

Kyoka gets badly injured during a fight against a powerful monster. However, she thinks Arihito is too inexperienced to help her and orders him to run.

While helping Suzuna rescue her friend, Arihito learns the surprising truth about Elitia.

Arihito tells his companions that he wants to turn Theresia back into a human, but they soon learn that they need to travel to District 4 to do so.

Arihito and his companions try to unlock a treasure chest. With Pharma's help, they acquire new equipment and finally are able to go to the third floor of the dungeon.

Arihito and his companions finally reach an uncharted territory. They encounter a new type of enemy that badly injures Arihito.