The Black Marker was an alien artifact discovered on Earth by the Earth Government in 2214. It was hidden to discourage alien belief. It was brought to public knowledge by Michael Altman who was contracted to research the Marker nearly 300 years prior to the events of Dead Space. It was the source of the codes that the Earth Government copied to create their own Markers which had the same devastating effects as the original.
The leader of the Circle, Jacob Danik speculated that the Black Marker forced evolution on Earth to create an intelligent species capable of creating more Markers with the ultimate plan of initiating a Convergence Event.
The Black Marker was found by Michael Altman and a team of researchers in the asteroid impact crater off the coast of the Yucatán Peninsula in Mexico. It was later concluded that the Black Marker landed on Earth approximately 65 million years ago and is what caused the mass extinction of the dinosaurs. The existence of the Black Marker was known to the locals that lived near its resting place for generations, but was never spoken about to outsiders and was referred to as "The Tail of the Devil". The locals tended to cross their index and middle fingers when they are speaking about it.
Altman's discovery spawned a religion known as Unitology that grew faster than any other religion ever formed on Earth. According to official sources, Altman was mysteriously assassinated by the government to silence the truth and he became a martyr figure to the religion's believers. In reality, the government had him killed by a Necromorph created by the Marker so they could intentionally use him as a scapegoat. The Black Marker was revered by Unitologists as an immensely powerful holy object which God sent to show that death was not the end. Various tests on the Marker led to it being reverse-engineered. The result was a functioning copy known as the Red Marker.
The Black Marker was classified as government property and although the Unitologists worshiped it, they only appeared to have pictures and possibly the leaked vidlog from Altman to base their beliefs on. As most of the data was classified, their conjectures and the comments of Altman caused irrational, hysterical ideas about the Marker to gain momentum. The Unitology religion offered vague promises of immortality, backed up by apparent scientific credibility which excited many previously purposeless and depressed people in the dry and impoverished world.
The Church of Unitology always wanted to get its hands on the Marker (Which was the reason why they are so excited by the Marker found on Aegis VII), though they seemed to have access to the Red Marker prior to the events of Dead Space. This suggested that they had agents in the government. Altman, after seeing the horrifying effects of the Marker sank it along with the floating facility that it was housed on so it could never cause harm again. Two Earth Government officials who supervised the project, Craig Markoff and Stevens made sure that the data of the Marker was copied so they could make their own Markers for more research.
The Black Marker's influence was similar to the Red Marker's. It was revealed in Dead Space: Martyr that there was a different force surrounding the Black Marker than just the ability to cause madness in humans. Altman thought that there was something in the human mind that caused the hallucinations which was a kind of defense mechanism that was activated in the human brain when it was in the Marker's presence. Altman was not immune, but he was able to resist the madness caused by it. It was possible that in all of these cases, there are actually two forces working on people's minds. This was shown when many people in Dead Space: Martyr claimed to hear two voices. One of these voices told the people to kill themselves while the other appeared to be trying to manipulate people into furthering its own interests or in the case of Isaac and the Red Marker, manipulating them into starting a Convergence Event under the guise of stopping the Necromorph threat.
The symbols on both Markers apparently represented DNA and the double-helical structure of the Marker itself alluded to this.
The Black Marker's current status was unknown. The Sovereign Colonies managed to excavate it from the facility ruins and use it for their own experimentation, eventually leading to their own Red Marker copies such as the Marker 3A found on Aegis VII.
- The Black Marker was completely unaffected when the piece was taken from it; however, it seemed to "think" it wouldn't be because it made one of the people, on the submarine taking the piece, go insane and kill both himself and his partner and write symbols all over the walls with their blood.
- The piece that Michael Altman owned was copied by Harmon and used in combination with the information saved from the sinking platform that contained the Black Marker to make the Red Marker.
- According to Michael Altman's analysis of the core sample taken from the Black Marker it has several unusual physical properties. Its structure is smooth both outside and within, the edges featuring a strangely uniform mineral vein structure. This substance is like granite in appearance but almost as hard as corundum, one of the hardest minerals on Earth. Due to the robustness of the Marker, it can be assumed all other Markers based on the black one are physically similar as the Red Marker could not be destroyed easily either.
- The Red Marker appears to be the color red because the element Bismuth was used to replace certain elements present in the duplication of the Black Marker.
- The Chicxulub crater is a real-life crater. True to its location in the book, it is the crater caused by the asteroid impact that supposedly wiped out the dinosaurs. In the book, the Black Marker was carried by the asteroid that hit Earth 65 million years ago.