The Dark Passage is an unfriendly part of space, formed by two anomalies: a large asteroid field and a network of Quantum Singularities. It is the passage between this asteroid field and singularities that is called the "Dark Passage", and the region has not stolen its name.
The Dark Passage is known to be a dangerous area, one that is best avoided. A ship's sensors usually go blind in many parts of the Dark Passage, which makes a passenger vulnerable to raider attacks, for which the asteroid field is well known.
The main species who reside in the asteroid field of the Dark Passage, are the Loxians. They have made the asteroid field their home and know perfectly how to navigate through it quickly and easily. They are known to raid any unfortunate ships they might encounter for food, supplies and sometimes to capture the ship. However, these Loxians are exiled from their homeworld for opposing the tight regime of their homeworld's government. Banned from their home, they retired to the Dark Passage for cover and safety, but as there is nothing valuable to be found, they can only survive from their raids.
The Quantum Singularity Network is also regularly visited by a species called Nigillians, who are very religious and believe the singularities to be the home of their Gods. They do not enter the singularity network, but they have built a religious temple on a planet near the singularities, called Sordinan. This is located on the outer side of the Quantum Singularity Network, however, and not anywhere near the Dark Passage area itself.
Another well known species that reside in the Dark Passage itself, are the Cardassians. While the Dark Passage normally blocks most sensors of ships and stations, the Cardassians heavily redesigned their space station in the region, called Vontak Nor, which has been placed inside the Dark Passage. Even so, they had to use unconventional solutions and even some theft of material, in order to achieve this.
Though the sensors are clearly rendered blind by the asteroid field and the Quantum Singularity Network, it is unknown how such two anomalies could come to exist so close together. The Cardassians believe it may once have been the place of a secret base, where new space ships were tested and launched.
When Cardassian Admiral Rugal and his 23rd fleet came to the Dark Passage in 2377, it was anticipated that they would be able to last without reinforcements for at least some years. Unfortunately, they did not even manage for three months. Vontak Nor and its ships was often harassed by Loxian raiders, but the Cardassians do not believe that the Loxians actually created the Dark Passage, or used it as a secret base, as they are too primitive for such advanced operations. Even so, these Loxians were still advanced enough to take the fleet of Rugal by surprise and neutralize almost 90 of his ships. Only a few ships of his fleet survived, under the Hideki Mora. Of any more threats in the Dark Passage, little is known, and the only one who has advanced knowledge of this area of space is Fleet Admiral Rugal himself, though he will be quick to change subject if this topic is discussed or he will answer that such information is classified. All he is willing to tell is that it would be unwise to underestimate the Cardassians in the Dark Passage, as they have still managed to remain there, despite the Loxian harassments.
See also: Loxians
The Dark Passage's Quantum Singularity Network seen from afar.
A closer view of the Quantum Singularity Network.
Cardassian station Vontak Nor inside the Dark Passage.
A view of the Dark Passage's asteroid field, with a nearby planet.
A Starfleet runabout navigating through the asteroids.
A ship attempting to navigate through the asteroid field.
Another view of the asteroid field, with the Quantum Singularitiy Network in the background.
Another Starfleet runabout navigating carefully through the asteroid rocks.