Hidden Floor

The Hidden Floor (숨겨진 층, Sumgyeojin Cheung) is a data world located inside the Hell Train. Only the Regulars who have cleared the entire Hell Express can leave their data in the Hidden Floor.

History
After going through Revolution on the Hell Train, Zahard sensed that he will become a godlike being, so he sought to preserve his human self. When one of the disciples of The Workshop found out about this concern of Zahard, he gave Zahard the Mirror of the Past as a gift. That mirror has the ability to store a person's present self within it.

After Zahard stored his image using the Mirror of the Past, several of his companions did the same. The Future King of the Tower left the Mirror in the last room on the Hell Train, so that only those who clear the Train may see the world within the Mirror.

When Zahard became the King, his fame soared and many Regulars left their data in the Mirror to meet younger version of the King in this artificial world. The disciple of the Workshop found out that the data were living inside the mirror, creating their own world. The disciple decided to protect that world and the Spell of Oblivion was placed on the room with the Mirror of the Past. Whenever someone who stored himself in the Mirror trys to reveal anything about that place, they forget everything about it. The Disciple also created a single door to that new world, along with only two keys. He gave one key to Zahard and another to the conductor of the Hell Train.

After hearing what had become of the Mirror of the Past, Zahard was amused and is said to have called it the Hidden Floor.

The Hidden Hidden Floor
Inside this virtual world, data Zahard and his companions grew tired of the huge increase in the numbers of newcomers. With the help from the outside, the Hidden Hidden Floor (숨겨진 숨겨진 층, Sumgyeojin Sumgyeojin Cheung) was created using another Mirror and data Zahard transfered there with only a few chosen.

Stages
The Hidden Floor consists of various stages. To advance to the next stage Regulars need to complete the quests. Completing quests makes white color fill the gauge on the Good and Evil Monitor. When they fill the gauge completely white, the Big Breeder gives the main quest to banish the Fruit of Good and Evil.

Data of Yu Han Sung found out that by filling the gauge black, instead of white, on the Good and Evil Monitor, Regulars can get the special Hidden Grand Quest, which also leads to next stage.

List of known Stages

 * Stage 1: Town of the Wandering Minstrel
 * Stage 2: Cold Land
 * Hidden Stage 2: Sweet Castle
 * Stage 3: Rough Land
 * Hidden Stage ?: The Palace of Spears
 * Stage 7: Labyrinth of the Minotaur
 * Stage ?: Town the Golden Dome
 * Stage 21: Seed
 * Extra Stage: Training Stage
 * Hidden Stage: Glitch Room

Fruit of Good and Evil
Fruit of Good and Evil (선악과, Seon-aggwa) is a quarantined place for the most dangerous individuals in the Hidden Floor. Batis was imprisoned here for going against the Big Breeders.

If Regulars in the Hidden Floor live a life that is evil, the giant eats the fruit and breaks out of his shell to punish them. However if they do good things like completing quests, the giant drags the fruit into the underworld. Regulars who achieve that can advance to next stage.

Bug Room
Sometime during his climb of the Tower, Urek Mazino visited the Hidden Floor. He promised the Big Breeder that he will not cause trouble, but when he is later informed that his data self will be unstable due to trouble in saving his data, Urek smashed the mirror in anger. This caused bugs, such as the continued existence of Urek's sworn enemy, which was supposed to disappear after Urek left. The sworn enemy is also weakened, compared to Urek. The bug also caused changes in the Hidden Floor, causing the artificial data humans to become more human-like than they should be.

One of the Big Breeders isolated these bugs into a room, dubbing it the Bug Room.

Notes and Trivia

 * The Hidden Floor is ruled by Big Breeders. They are compared to Guardians.
 * The Hidden Floor is inhabited by data of Regulars and artificial data humans.
 * Every Regular has generated a Sworn Enemy, based on their past.