Devil's Labyrinth

Note: Before Chapter 16-35 was call it "Seryuu City Labyrinth" according to the name of the city

A dungeon that was magically formed within Seryuu City when an Arm Demon appeared. During its formation, the demon had also trapped various people inside the dungeon that was within the vicinity during its creation, including Satou.

Info
Entrance: Middle of Seryuu City

Dungeon Master: Arm Demon/Senior Demon that attacked the lord's castle in Seryuu City.

Contains a gate with 『Thou hast to answer my question if thy wish to continue』written on it. The riddle to open it is 『Shonimu is righting the tree, Dareson is eating the fruit, Yurato is planting the seed. Correct our right position.』The key items to solving the riddle are each contained in different rooms. It is unknown what the correct order to placing each key item is since Satou used the [Deriddle] skill to solve it.
 * Room with statue on top of a pedestal in center of a room with a depressed floor except at center and Wandering Roots, tree root like creatures, surrounding the statue. This is the room closest to the gate. The statue is the key item to solving the『tree』part of the riddle.
 * Square room with a Lv40 Stone Golem, 3 meter great-majin look-a-like monster, in the center of the room. The center is of slightly lower floor level. The Stone Golem has [Physical Damage Halved] and [Spirit Damage Invalid] unique skills. After defeating the Stone Golem, a blue gem can be obtained to solve『fruit』part of the riddle.
 * Room with treasure chest in center and surrounded by traps. There is only one safe path leading to the treasure chest. The treasure chest is actually a Mimic, which Satou considers a regular dungeon monster. When defeated, it evaporates into purple smoke and leaves behind a black stone, which is the key item to solving『seed』part of the riddle.

The dungeon master is in a room containing an alter with candles around it. When one enters the room, the candles light up with blue flame and a magic circle with purple light, from which the demon appears from, emerges on the alter.

Satou first entered the labyrinth when it first appeared and entered it again at night, when nobody was around, to defeat the dungeon master.