Combined Doom Timeline (Spoilers)
Edit Note – I had to do some major edits of the post after digging up the original Doom Manual stories, finding some mistakes in the process. It mostly concerns details regarding Mars and Final Doom locations. The Doom 3 timeline is included now as well – I'm not sure how well it works, so each Doom 3 and Doom 16 entry is marked so you can decide on that more easily.
Edit Probably the most interesting detail I've found so far is that Final Doom took place on Jupiter's moon Io in 2023. The parts of the suit that appear similar to the original Doom Marine armor have stamps that say IO logistics Manufacture. Near one of them it has what may be a date stamp that says "8623". This could indicate that those components were made on Io on June 8th 2023 (or August 6th). This could be a deliberate hint on Id's part. Edit
I'm a little late to the party in playing Doom 2016; I got it as a Christmas gift. I loved the originals, and I still remember their plots quite well, so I was excited to play what I thought was a reboot. The beginning of the game and the "Praetor" suit immediately confused me however… it was apparently pulled out of hell but is covered in Roman numerals, serial numbers, English text (including corporate logos), and has a modern-style head-up display with English readouts — it's clearly a product of human manufacturing on Earth. I think, holy crap, this is a sequel to Doom 64! At the end of Doom 64 Doomguy stayed in hell "forever", so they must have retrieved him.
Thinking wow, this is pretty damn cool, it's the original Doomguy, I went online to see people's reactions, but it looks like people have been arguing about this since the game came out. Reading the arguments, their sources, and looking at images spoiled the game of course. To make things worse, I haven't found a take on it that really makes sense to me, so I did my own reading, and this is the most parsimonious explanation I can think of. A timeline at the end of this post for reference (Source: Doom Wiki and Doom Manual Stories).
The timeline basically starts in the 2020's when the UAC established research and nuclear waste outposts on Mars, Phobos, and Deimos. Experimental portals/wormhole technology is developed to transport resources directly back to Earth, but they accidentally connect to a parallel universe that at least strongly resembles the mythical Hell. Demons invade.
Phobos is overrun and a large chunk of Deimos is pulled into Hell. Marines launch from an outpost on Mars and are decimated when they reach the surface – leaving the Marine alone. He proceeds to kick ass from Phobos, to Deimos in hell.
The Marine gets back to Earth and finds it being invaded, with major cities all over the world under attack. He gets really pissed about his dead pet bunny at one point, then kicks demon ass on Earth, eventually killing or disabling the Icon of Sin.
Final Doom events: The UAC is reformed under new leadership and the Plutonia experiments begin. The UAC attempts to develop particle accelerators that can destroy Hell portals as soon as they form, but the experiment fails, and demons make it through.
Later, the UAC moves its research to Jupiter's moon Io in 2023 where they develop strategies to prevent Demon invasions by sheer military force. However, a massive Demon warship arrives in orbit from an unknown location and invades the Moon. The Marine, now a Commanding officer, stops the invasion once again.
The UAC stops its research and begins covering the cause of the invasions up (according to the story of Doom 64), and Doomguy suffers from Hell-induced PTSD from seemingly endless battles with Demons. Meanwhile, the UAC continues their cover up operation, sterilizing its research facilities with radiation. In the process they miss a surviving demon known as the Mother of Demons, a sort of "demon queen" that can spawn and resurrect demons. Another demon attack starts. Doomguy gets pulled back into service, kicks more demon ass, destroys the demon mother.
Unable to live a normal life on Earth, the Marine decides to remain in hell "forever" to keep kicking demon ass for eternity.
Earth apparently recovers over the next 70 years. I assume the UAC and the government covers the demon invasions up as – I have to assume – some science experiment gone wrong, not an invasion from some demon realm. Mars and its moons remained untouched until 2095, when Argent energy is discovered and the UAC begins harvesting it. They discover the remains of an alien civilization on Mars in 2104. And if Doom 3 is included in this, they establish Mars city. This is followed by the rediscovery of a hell portal in 2145. This time, the UAC tries to study Hell in a controlled, scientific way via expeditions, which led to the retrieval of the Doom Marine who remained in hell in the 2020's.
This seems pretty straightforward to me, but there are some sources of confusion, but I don't think they're really problematic at all.
1) Found demon text says the suit was made for the Doom Marine in hell by a "wretch", perhaps a demon who betrayed his kind. This makes sense of the armor's hybrid appearance: It has elements from the original Doom Marine's armor, complete with logos from the company that made it and serial numbers, but also chitinous plate segments and tubes somewhat like the armor of the mancubus (demons make chitin armor). This also explains why it can harness "Argent energy" as a power source.
2) The portals the demons use seem to be, for all intents and purposes, a form of "wormhole", a shortcut that allows for instant travel between two points in spacetime or between different universes. This is evidenced by the gore nests which show a spherical portal that connects to Hell. Any portal of this sort would necessarily connect two points in space AND time. Some of the game lore says the Doomguy traveled through worlds and time. Remember that in real life, time is relative. What this means is that hell could connect to Argent D'Nur many of thousands of years ago, then Earth in the 2020's, Earth in the 2140's, while still allowing the Doom Guy to remain in hell for an unknown amount of time, perhaps "eons", all without violating causality, because he never returns to a time before the events of Doom 64.
3) The cyborg demons seem to have a different origin than the originals, but only partially. Remember, they're not "natural" demons: they're a result of human technology being incorporated into them, both in the original series and Doom 2016. Hell in the original series is shown being a sort of medieval tech world, but the demons immediately began incorporating advanced human technology, which is why the UAC bases on Deimos looked like a hybrid of medieval tech and 21st century technology. The Doom Marine ended the invasion, apparently destroying these demons. In the 2140's, the UAC itself began experimenting with demons, creating their own cyborg forms analogous to the cybernetic hybrids of the 2020's.
4) While the demons of hell seemed to be the root of hell and demon beliefs, the night sentinels might be the source of angel myths, complete with a member of their order who betrayed them, resulting in the Icon of Sin (loosely analogous to Satan). They have a different armor style lacking any English text, and they use swords. The segments between their armor have a strange flesh-like quality, suggesting they are a different species entirely. They would seem to be another civilization that, like Mars, and like the Deimos base, was destroyed by Hell.
5) Along with the armor, another really big hint at a connection to the previous games is the dead/dormant Icon of Sin.
6) Some weapons that were prototypes in the 2020's reappear. A lot of technology may have been lost when the demons destroyed the UAC facilities, with the tech subsequently being rediscovered during the next century.
2-1,000,000 B.C. – Ancient Martian civilization is built.
400,000 B.C. – Height of the Martian civilization.
90,000-10,000 – Ancient languages develop on earth, some may have originated from Mars.
2018 – The military, UAC's biggest supplier, has used the remote facilities on Phobos and Deimos to conduct various secret projects, including research on inter-dimensional space travel.
2019 – Samuel Hayden is born [Doom 2016].
Strangely, Phobos is depicted as if it had been terraformed somehow. Doom 64 has a “Terraformer” level that seems to be on Phobos. This could be an attempt to explain the inaccurate depiction of Phobos.
2019 – The Marine assaults a superior officer, and is transferred to a base on Mars, home of the Union Aerospace Corporation.
2021 – July 1 – DOOMNL 01-D19305-1C is published.
2022 – March 15 – Mars receives a message from Phobos base stating that the base under attack and requesting backup. A few hours later, the marines land and try to stop the invasion. The Marine is ordered to stay behind and protect the perimeter. The marine forces are wiped out or turned into monsters. Planetary authorities send the final Marine the new DOOMNL 01-D19505-1D replacing earlier manual (now including briefing for the Marine, and 'images from the invasion captured by remote video cameras. The video data was computer analyzed by the UAC and the results are provided "here and only here"). The Marine leaves the escape pod vowing to destroy the invasion force.
Doom Begins – locations include Phobos, a section of Deimos pulled into Hell, Hell itself, and Earth.
I say a section of Deimos despite the manual saying it "disappeared from the sky" because the end game image shows a chunk of Deimos above Hell, not the entire moon.
Doom II Begins – Invasion of Earth – Billions are killed
No Rest for the Living begins – Doom Marine returns to Hell.
Plutonia Experiment begins on Earth – the experiment is a failure.
2023 – TNT:Evilution begins – events occur on Jupiter's moon, Io. A Demon warship arrives in orbit around Jupiter and attacks. The Demon ship is from an unknown location.
The Marine is decommissioned and suffers from depression and nightmares. The military DOOM Episodes are classified. The UAC's bases are sealed, and quarantined by radioactive bombardment.
Some Years Later – Doom 64 begins – Doom Marine is re-commissioned to stop a new threat, from a deep space (apparently Phobos) installation where he once fought the demons.
The Doom Marine defeats the Mother Demon and decides to remain in Hell forever to prevent future invasions. Supposedly the UAC covers up the Doom incidents, perhaps by attributing them to something else, such as genetic or military experiments gone wrong. Earth recovers over the next 60-70 years. The Doom Marine is trapped in Hell “forever”, and if he is the same as the Doom Slayer, he traveled “across worlds and time”. Mars remains uncolonized during this period.
2095 – The Argent Fracture is discovered. Argent plasma was discovered in a trench on Mars by an expedition from the SS Amundsen [Doom 2016].
October 29 – Construction of Phase One, Alpha Labs begins on Mars [Doom3]
2096 – The Union Aerospace Corporation established an outpost on Mars to extract Argent plasma from the Argent Fracture [Doom 2016].
2104 – The explorations of the caverns in 2104 led to the discovery of ancient artifact codenamed U1, the Soul Cube, along with stone tablets written by the ancient Martian civilization [Shared by BOTH Doom3 and Doom 2016].
2115 – Martian Civilization was first discovered [Doom3].
2118 – Steve Jenson is born [Doom3].
2120 – Construction on Mars City begins [Doom3].
2127 – The Argent Tower is completed . 6 Months Later – Samuel Hayden transfers his mind over to a cyborg to continue his existence, after his body breaks down due to Stage 4 Cancer [Doom 2016].
2130 – July 17 – The Alpha Labs are built. [Doom3]
2136 – The Advanced Research Complex is completed [Doom 2016].
2139 – Project Mercury, was built in Delta Labs, and became operational [Doom3].
2143 – The Corrax tablets are retrieved from Hell in a UAC Automated Survey [Doom 2016].
2144 – January 1 – Research on a partial Imp remains [Doom3].
February 5 – Hellknight (partial) research [Doom3].
July 28 – Series 3 Plasma Gun information video is released [Doom3].
November 2 – Research on the Living Dead [Doom3].
2145 – The first Project Lazarus Manned Expedition is sent to Hell. The expedition ends with complete loss of human life, but achieved its mission. The sarcophagus of the Doom Marine is recovered from Kadingir Sanctum [Doom 2016].
June – 21:00 hours UMT. Experiment in the Delta Labs triggers an unknown event, resulting in the systematic invasion of the entire facility. Marine forces are deployed to hot spots around the facility, with many teams encountering heavy resistance. Bravo Team was ambushed in EnPro facility while searching for survivors. There was only one survivor of the team. [Doom3]
July 12 – Research on the Imp [Doom3].
August 21 – Ancient Civilization video is produced. AM3 Series Portable Power Plant video is produced [Doom3].
September 27 – Revenant research [Doom3].
October 5, 2145 – Specimen Stasis Museum video is produced, Soul Cube video is produced. Tablets video is produced [Doom3].
October 10, 2145 – BFG 9000 Briefing video is produced [Doom3].
October 13 – The first incident occurred on October 13th, 2145 at the Exis surface tunnel. One of the construction workers, Bill Sanders, was offloading a shipment of steel supports when a procurement manager stopped him. In the heated conversation that followed, Sanders grabbed a nearby pickaxe and lunged at the manager. Luckily the argument beforehand generated a sizable crowd, and when Sanders attacked the manager, a number of men were able to subdue him [Doom3].
November 6, 2145 – Anthony Garza, Phil Anders/Phil Anderson, Bob Thompson Jenny Lin broke into a supply cabinet containing emergency weaponry supplied to the local security teams. For reasons unknown she then became hostile and killed two security officers. Another security officer was injured while bravely putting himself in harm’s way. Technician Lin was also killed [Doom3].
November 15, 2145 – The Marine arrives on Mars on Transport 4409 at 6:18 MC, he was transferred as punishment for assaulting a superior officer for ordering his soldiers to fire upon civilians, and to replace another soldier. He and his body cast were shipped to Pearl Harbor, while the Marine was transferred to Mars, home of the Union Aerospace Corporation [Doom3].
DarkStar is scheduled to return to Earth destination Burns Flat, OK at 18:55 MST [Doom3].
+6 hours post invasion, Bravo Team is ambushed, Bravo Marine (ID# 6703x-02) is the only survivor [Doom3].
November 20, 2145 – The Recon Zulu marine team found only one survivor, a Marine Corporal. Important UAC personnel such the company's lawyer and counselor Elliot Swann and his bodyguard Jack Campbell, who arrived hours before the outbreak to make an assessment of the whole Mars operation and enact damage control if necessary, were found dead. Master Sergeant Thomas Kelly and other Delta Labs scientists were also found dead. The marine team had no information regarding the fate of Dr. Malcolm Betruger, the chief scientist of Delta Labs who – unknown to them – had become the demon Maledict [Doom3].
DarkStar scheduled to make it to earth 13:00 CST [Doom3].
2146 – May 1 – An orbital probe detects a faint unidentified signal broadcast from the abandoned Site 1 Complex [Doom3].
August 8 – The UAC announces the renewal of its Mars research program. Dr. Elizabeth McNeil is chosen to lead the primary assessment team [Doom3].
Industrial accident related deaths in the Foundry dropped significantly thanks to new UAC safety protocols where employees exposed to dangerous materials are sent to the Lazarus Labs [Doom 2016].
September 12 – Elizabeth McNeil welcomes personnel to the Site 1 Expedition [Doom3].
2146 – The first Project Lazarus Tethering Operation is conducted. Pinkies are discovered for the first time [Doom 2016].
March 17, 2147 – Resurrection of Evil begins [Doom3].
2147 – The second Project Lazarus Tethering Operation is conducted. The expedition ends in an confrontation with the Hell Guard [Doom 2016].
2148 – The second Project Lazarus Manned Expedition is sent to the Great Steppe. The expedition ends with similar losses. The petrified remains of a Baalgar demon is recovered [Doom 2016].
2149 – February – The Argent Facility – UAC base had its last accident.[Doom 2016]
October – Doom 2016 Begins.[Doom 2016]