Image by deviantart user, PavellKiD
Derelict spacecraft are truly the dungeons of space, and the Space Hulks are the truly legendary dungeons of the stars. They are ancient, titanic starships that were built by an unknown species that possibly predates the Prometheans. This massive starships either drift through space or randomly jump in and out of space time via some unknown method. As far back into the records of even the oldest space-faring species, Space Hulks have been cataloged, studied, boarded, and explored. While some corporations have made their fortunes and reputations from the tech scavenged from these ancient wrecks, even more corporations and far more explorers, scientists, and mercenaries have lost everything: their credits, their lives, and their sanity on these ships.
There are 16 known Space Hulks, but it is theorized that this may not be the total number of hulks in the galaxy. It has also been theorized that there may every well be many other hulks in the cold dark of space between galaxies, since there are several researchers that believe that the space hulks originated from another galaxy, be it Andromeda or another nearby dwarf galaxy. Every hulk is gigantic, large enough to generate their own gravity and atmosphere in many cases, but each one is now far larger than they originally were. Over the eons, these ships have collected other spacecraft (likely predominantly the ships of explorers and scavengers that have been lost on their endeavors) as well as asteroids and other space debris that have become lodged into the hulls and therefore have become part of the craft. They are not unlike museums drifting through space and in an out of our reality. Thanks to their nigh-unimaginable age, they hold untold treasures of technology, history, genetics, and weaponry; all ripe for the picking should an enterprising crew happen to find one.
Most Hulks, save one, either drift through space or (more commonly) shunt into and out of reality seemingly at random. The means by which these immense starships do this is completely unknown. One moment, the Hulk is sitting in space, and then comes a building of energy and the ship appears to slip sideways into a tear in the fabric of space and is gone. That hulk may reappear on the other side of the galaxy within days or not for centuries. There so far has been no pattern that can be discerned from the comings and goings of a Space Hulk. They simply appear and disappear at random. Even the most widely accepted theory on their method of travel (dimensional shunting) has not been proven. All that is certain, is when the ship disappears, it's not as if it is cloaked; it simply isn't there anymore. The few that have been on a Hulk as it traveled in this manner state that space is different. It ripples ever so slightly as if the Hulk were suspended in a calm body of water. The alignment of the stars are wrong, and some will wink in and out as if someone is turning them on and off like a light. A strong feeling of disorientation and "wrongness" permeates this other dimension or reality, so much so that over 85% of those that have entered this other realm have been driven insane by the experience.
Out of the 16 known Hulks, two have been destroyed, one by altering its course into a nearby star, which nearly killed the star in the process (Devastator), and the other by it re-entering our reality too close to a black hole (H-13). Even though there are many that would risk their companies, their nations, and their lives to study and plunder the secrets of a Hulk, everyone fears the appearance of one of these mammoths in their system. This fearful reputation is well deserved. It was the Space Hulk, Tyrannus, that introduced the worlds of the Concord to the Tyranid menace. The Hulk, Primal Necropolis, carries a plague parts of its interior that kills with 99% effectiveness and those that survive and typically driven insane by the ravages of the disease. Alien horrors and virulent plagues are only two of the dangers of a Space Hulk. Explorers must also be wary of unstable bulkheads that can open out into the vacuum of space, still active internal defenses, pirates and other not-so-noble explorers, and disappearing into some unknown reality whenever the Hulk decides it is time to leave. Hulks have earned their infamy for all of these reasons and more, but the rewards for those who can plumb the depths, even ever so shallowly, and escape with not just their lives, but with artifacts or data have made the fortunes of many.
Below is a list of the known Hulks and a few details about the more (in)famous hulks.
Devastator was the first Hulk in recorded history to be destroyed. This Hulk housed an army of mutated marauders known as Death Knights. These humanoid creatures donned armor that appeared to be a conglomeration of their own armor and pieces scrounged from the inside of the Hulk. Wherever Devastator appeared, these vicious and bloodthirsty beings would swarm out of the hulk and lay waste to any nearby worlds. The Death Knights appeared to know when Devastator was about to disappear, as they would break off attacks to return to the hulk even when they were on the cusp of domination over the defense forces of a local system. The Protoss Collective finally ended Devastator's reign of terror by using mass drivers to hurl enough asteroids and proto-planets into the hulk, forcing it on a collision course with the star Ainuri, which nearly caused the star to destabilize and go super-nova far sooner than it would have naturally. Sadly, the increased solar radiation burned off much of the third planet's atmosphere, killing billions of Protoss citizens in the process.
Tyrannus is infamous for being infested with the insectoid-like beings, predominantly the dreaded Genestealers. Genestealers propagate their species by using barbs at the end of their long tongues to inject their genetic material into a host. Over time, the hosts DNA is re-written into that of a Genestealer. This process typically take a week or two, but there are some tales of Genestealer infections transforming a victim in only hours. The Concord issued Emergency Decree #18 after Tyrannus appeared in the Moltanik system and the Hive swarmed forth, completely wiping out three colonies in the system and destroying a space station. The decree states that if any Concord member detects the presence of the Hulk, Tyrannus, that the Concord Navy is to be contacted at once and emergency war-time defense strategies should immediately be enacted.
Primal Necropolis is largely an enigma. Of all the known Hulks, save the Aegis of Time, it holds more derelict ships on its hull. The disease known as the Primal Curse hangs in the air. No one can explain how a disease that live for so long without a host, but the effects are clear: hemorrhaging, hallucinations, loss of muscle control, and finally death are all effects of the disease. As said above, this plague has a 99% kill rate in those infected. The disease is also very virulent outside of the Hulk. There is a crater on the planet Farson III, where a colony was obliterated from orbit due to the rapid spread of the disease. So little of this hulk has been explored, but those that have entered it say that the hallways are littered with the bones of those that attempted to plunder the Hulk, some of the species were totally new to researchers. Primal Necropolis is another hulk that is off-limits to citizens of the Concord by Emergency Decree.
Aegis of Time is an anomaly among Space Hulks. It orbits the star of the Ylindril system between the fourth and fifth gas giants in the system. It has orbited Ylindril for at least the last 500 years thanks to evidence found among the remains of those that explored the hulk before an exploration ship re-discovered it 52 years ago. This hulk is also an anomaly for being far less deadly than any other hulk. It still has its dangers, but the Aegis of Time has been deemed safe enough to house a full time science team. Over the last couple of decades the hulk has turned into a sort of space station in the sector. Even though this hulk has been studied non-stop for the last 52 years, only 36% of the craft has been properly mapped and explored. There are still vast areas of the craft that are closed off in spite of the best efforts of Concord scientists and military forces. Thanks to the artifacts and remains found in the corridors and rooms of the Aegis of Time, 15 new species of intelligent life have been discovered (although the age of the remains and the lack of any other confirmed sightings leads researchers to believe that most of those species may no longer exist), technological discoveries have lead to more efficient power packs for weapons and gear, and that's not even mentioning the various historical artifacts in the forms of vids (taken from the remains), data-chips, and pads.
Fordham's Folly is the latest Hulk to be discovered. It appeared deep in the Oort Cloud of the Sol System. Commander Travis Fordham of the Sol Systems Alliance Navy fought hard to lead a team of scientists and soldiers to explore the Hulk as he has always been enthralled by the legends of these craft and therefore desperately wanted to explore one. The team was only on the hulk for two hours before it shunted away. The team was feared to be lost when the Hulk reappeared in the same location just minutes later. A frantic call for help was received from the hulk and an extraction team was sent in. Commander Fordham was the only person found, alive or dead, although his armor was caked in blood. Cmdr Fordham couldn't explain where his team was and appeared to have no recollection of the time the hulk had disappeared. All he would say was that "the shadows" over and over. He was deemed to be suffering an extreme case of PTSD and was placed into psychiatric care at Bethesda Medical on Earth. Cmdr Fordham would become suddenly violent and killed three staffers, forcing him to be placed into solitary confinement. The once storied career of Cmdr Fordham came to and end 10 years to the day after his rescue from the Hulk. He was discovered in his cell with a snapped neck. It was assumed that he somehow committed suicide, but signs of a struggle suggest he was murdered. The vid feed in his cell showed Cmdr Fordham suddenly becoming agitated and frightened. The vid goes slowly dark, although there was nothing wrong with the lighting or the vid feed, until nothing can be seen. All that is heard is a scream and a crack and the feed suddenly clear up to show Fordham dead in the corner of his cell.
As for the Hulk, after the extraction team rescued Cmdr Fordham, it disappeared. It has only reappeared one other time (that anyone is aware of), in the Wrinlovex System three years after its appearance in the Sol System. It was monitored for for a few minutes until it disappeared again.
The Curse of Khaine is a hulk first encountered by the Eldar in their home system. Details are sketchy, largely in part because the Eldar do not speak of their home system except in riddles and half-truths, but the Eldar feel the appearance of the Curse of Khaine directly lead to the downfall of their society. Exarch Tolis of the craftship, Eleshaar, gives the best depiction of the Curse of Khaine and why his people fear it so much: "The Curse of Khaine brought forth the blight that ended the Eldar Empire and sent us on our exile to find a new home in the cosmos. It was manned by the damned and it spells the doom for all that encounter it. Do not search for the Curse of Khaine, but know that the day will come when it will appear and all of us will have to peer in the darkness and see the terrors that await us." As far as is known, the Curse of Khaine has only be witnessed by the Eldar, so it's possible it's just a metaphor for something whatever was plaguing Eldar society at the time of their fall, but since the Eldar are so secretive about their origins it must be left up to pure speculation until now.
Danar'sidai is the only hulk that has never shunted for as long as it has been tracked by any of the Concord societies. It plods along at a rate of about 6 AU's per year. Danar'sidai is the name given to the hulk by the Minbari, who discovered (well, the first of the Concord species to discover it, that is) it back in the early days of their baby-steps into the Cosmos. The name mean "Deathbringer." The Minbari have tried to destroy the craft many times, but have so far been completely unsuccessful. Out of all of the Hulks, only the Aegis of Time has been more thoroughly explored, however, no map of Danar'sidai is useful. The interior of the craft seems to shift and change with time. A map that may have been perfectly good 12 years ago, may be virtually worthless now; a quality that has baffled every scientist that has ever studied the hulk. The hulk is a hotspot for explorers, pirates, and plunderers though looking for ancient relics and tech thanks to its predictability. That appears to be where much of the danger stems from: other explorers. However, the Minbari that first explored the hulk ran into strange alien beings who had the appearance of having lived on the hulk for a long time. In fact, teams of raiders and other explorers have gone missing in the depths of the hulk. It is possible that these lost folk have met with others, and possibly have built their own colonies inside the hulk; with the strange occurrences surrounding these titans of space, it appears that anything is possible.
The other eight hulks have never been explored by Concord members. Other cultures may have names for these other hulks, but none of that information has been made available to Concord historians and researchers. What is known is that if any of these other hulks enter into Concord space and are discovered, that it is Concord law that the Navy be notified immediately and that the local security forces secure the hulk until the Navy can arrive to properly assess the situation. With the myriad of dangers that these starcraft can house inside of them, it is no wonder that the Concord wants to keep foolhardy explorers plumbing the depths and unleashing unknown horrors upon the Concord, and the galaxy at large.