Seiken no Sword Labyrinth

is a Japanese light novel series written by Natsuki Mamiya, with illustrations by Kei Kotori. The series began publication on July 10, 2015 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
Capture the huge dungeon "Sword Labyrinth" created by the old gods!

There are things in this world that are beyond the reach of human intelligence. Called "Sword Labyrinth", it is a dungeon that exists in the giant ancient relic "Sacred Sword Gram" that pierces the sword city Sigurd. Many adventurers challenged and disappeared to solve the mystery of this labyrinth, which is a holy sword but produces monsters. The father of a young boy, Alex, who lives in the sword capital, is also one who disappeared into the labyrinth.

Ten years later, Alex, who has grown into a silversmith who manipulates silver, enters the labyrinth after encountering a mysterious girl, the Queen of Swords, Celestia, who is said to be a dungeon master. Without knowing that the adventure of finding a father would bring about new disasters ...