Dark Ocean

In Digimon Adventure 02, the Dark Ocean (暗黒の海) is a world that has the power to bring twisted thoughts to life, as well as to magnify and corrupt them, and to inverse the natural order of things.

It is ruled by and plays a central role in Digimon Adventure 02 as one of its three main dimensions, along with the Real World and the Digital World.

It is first within the story when Ken unlocks the full potential of his Digivice, after the death of his older brother, Sam, due to the influence of the Dark Spore.

Next, it is seen when Kari is pulled into it due to holding too much inside her. She was only rescued due to the intervention of Patamon, Gatomon and T.K., her partner digivolving to her Ultimate-leveled form to defeat an Airdramon and repel the Scubamon, Digimon who worship and serve Dragomon.

Shortly later, it is considered a dimension of his own among the many that exist when the DigiDestined ponder about their battle against the Digimon Emperor and the prophecy Wizardmon had told them and what would happen if they were to merge into one, the result being chaos, turmoil and mayhem.

Some time later, it is once again seen when Ken falls into despair and darkness due to the influence of his inner dark self. Kari follows suit, with both suffering intensely until Yolei snaps them both out of it. In the latter's case, it triggers the DNA Digivolution of Aquilamon and Gatomon, merging them into Silphymon and defeating the Control Spire-built Blossomon sent by Arukenimon and Mummymon.

Later still, it is used as a last ditch effort to defeat Daemon when he proves too strong for the DigiDestined to defeat and destroy, even with their combined might. It succeeds, trapping Daemon into the Dark Ocean and banishing him to Dragomon's domain, finally putting an end to the threat the Demon Lord posed to Earth.

Innsmouth
Insumausu (インスマウス) is a place in the Dark Ocean.