Last Dungeon e Youkoso

is a Japanese light novel series written by Suo Tsukasa, with illustrations by Machimura Komori. The series began publication on August 10, 2015 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
The boy, Satoru, has two faces.

In the daytime, a high school boy with a "little" problem. However, at night, he is summoned by the Demon King's daughter, Loretta, and protects the labyrinth from adventurers by making full use of monsters and traps while helping her, "Dungeon Master". Satoru continues to use his wisdom today to destroy the stupid humans who are trying to overrun Loretta's home, which is weak and kind.

However, Satoru's "Labyrinth Management" is quite promising, as good monsters do not gather at the interview, foolish Loretta is trapped without permission, and a mysterious super strong adventurer named "Supreme King" appears. It's difficult ...?