Dark Area

The Dark Area (ダークエリア) is a "graveyard of deleted data" full of evil energies, and is the prison in which the most dangerous and evil Digimon are confined. It is located within the Digital World, below the Net Ocean. The center of the Dark Area is the den of demonic Digimon, who are led by the nobility of the Dark Area. Most of the nobility lead legions of the dark army of demons known as the "Nightmare Soldiers".

Long ago, Lucemon and Daemon led a rebellion of Demon Lord, Demon, and Fallen Angel Digimon against the creator of the Digital World, and were imprisoned in the Dark Area along with many of the other Demon Lord Digimon. Other Angel Digimon who rebel and fall from grace are imprisoned within the Dark Area, where they also become Demon Lord or Fallen Angel Digimon,  and it is said that those who attempt to reach the Golden Land but fail Crowmon's "Threefold Trails" are dispatched to the Dark Area as well. Even the data of Digimon consigned to oblivion by the Seven Great Demon Lords is not reincarnated, but is sent to the center of the Dark Area, where it becomes the flesh and blood of the Demon Lords.

Digimon Frontier
The Dark Area in Digimon Frontier is a location that lies at the center of the. It is where the primordial chaos and the world's corrupt souls gather. The tyrant is sealed here by the  after his defeat. Within the Dark Area, Lucemon plots his revival by tasking his servants—first, a corrupted, and second, the wayward —to gather the world's data for him. As he attains more and more power, the Dark Area seals him less and less until he is able to spread his power into the world itself. With the scanning of the entire world, Lucemon himself is freed from his prison. After digivolving to his, Lucemon heads to the Dark Area and uses its power to form a tunnel to the Human World. The force one final battle here, where  saves his friends at the cost of his soul, which is scanned by Lucemon. The DigiDestined assume their strongest form,, due to Koichi's sacrifice. Susanoomon defeats Lucemon, bisecting both him and the Dark Area. The Dark Area appears to be purified, but its power is instead drained into the dark half of Lucemon's data, birthing, whose "Gehenna" orb is a miniature manifestation of the Dark Area.