The Entire Doom Story Explained

In the opening moments of the 2016 Doom reboot, the Doom Slayer wakes to discover the latest mess he'll have to mop up. Not even five seconds into Samuel Hayden's briefing, the Slayer shoves the monitor aside, finds himself a shotgun, and cocks it to the beat of his own theme music. It's one of the most badass scenes in gaming.

No on would blame you for thinking, "Oh, I know exactly what my objective is in this game, and it mostly involves performing profane acts on every demon I see." Believe it or not, the Doom franchise does have a story woven through each new entry, and it's slightly more involved than you might think. The narrative is complex enough that a debate still rages over where certain games fall on the timeline or if the protagonist is even the same person throughout. 

Here's what you might have missed during your relentless search for keycards and chainsaws. Sit down and enjoy this tale about the happy boy they now call the Doom Slayer.

The story begins in the distant future. Space travel is pretty much down pat. The hero — who, right now, is best referred to as the Marine — is, well, a Marine. Tough as nails, Semper Fi, gung-ho, the whole nine. Things go awry for the poor man's career, however, when he assaults a superior officer for ordering his men to fire on innocent civilians. 

The USMC ships the Marine off to Mars to be bored out of his skull as a glorified security guard for the United Aerospace Corporation, a conglomerate that has its dirty little fingers in every pie. That includes secret experiments into inter-dimensional teleportation technology on Mars' moons, Phobos and Deimos. The experiments aren't going well even at the best of times, with the people who pass through the two working portals on each moon emerging physically or mentally broken. 

One day, the situation gets exponentially worse when Mars receives a distress call from Phobos stating, "Something fraggin' evil is coming out of the Gateways." That's exacerbated by the fact Deimos just straight up vanishes from the sky. The Marine and his buddies check out Phobos, with the Marine left guarding the perimeter. When the radio eventually goes silent, the Marine has no choice but to take a pistol and see what's going on for himself. No pressure, though.

The Marine is met with a harrowing scene inside the Phobos base. The few remaining humans are non-verbal and hostile, attempting to shoot their former squad mate on sight. A host of snarling, disgusting demons who like to throw fire at you joins them. Still, there's enough weaponry lying around the place for the Marine to make quick, steaming work of most opponents. Just think of your average hamburger grinder and imagine that grinder has a Marine's face. That's basically this series when it's not plot time.

Eventually, the Marine finds the portal leading to Deimos, which (surprise surprise) is crawling with demons, sacrilegious imagery, and pulsating architecture. After fighting through the Deimos base and killing a Cyberdemon abomination merged with some human tech, the Marine finds out the awful truth: Deimos has been teleported to Hell itself. 

Thankfully, the Marine has some demon-killing experience. He rappels down to the surface and fights his way to the ugly sucker who plotted the invasion: the Spiderdemon. After leaving it a bloody pile of guts, the Marine takes the portal back to Earth and lives happily ever after. Just kidding! Hell has already invaded Earth, and billions of people are dead. 

With Earth transformed into a literal hellhole, humanity's leaders get the bright idea to take what's left of the species, launch into space, and wait for the whole ordeal to blow over. A decent plan, except for the fact demons have surrounded Earth's last operating spaceport with a barrier of flame. Not a huge deal for a guy that's already killed his way through a legion of demons just to get to Earth, so the humans do manage to take off into the stratosphere.

Not long after, the Marine gets a message from the human leaders stating they've found the source of the invasion: a portal in the Marine's hometown. Since there's no way to close it from the Earth side, the Marine treks straight into Hell once more to find the source of it all: the Icon of Sin. After one of the most annoying fights imaginable, the Icon collapses. The Marine finally make his way back to Earth with the rest of his species to begin the rebuilding process.

The Marine tries to recover but, despite all the tests and treatments, he still suffers from nightmares. Meanwhile, back on Mars, the demon problem persists, prompting the UAC to blanket Phobos and Deimos with apocalyptic levels of radiation. Unfortunately, the radiation has a nasty habit of blocking the UAC's sensor equipment, eventually allowing the literal Mother of All Demons to slip into the dimension.

The Mother resurrects every single slain monster, making them stronger and nastier than ever. Thankfully, the Marine's got some serious mental issues to work out, and this little incident is just the catharsis he needs. After killing his way through the demonic horde, he finds himself back in Hell, face to face with the Mother — a face he takes great pleasure in rearranging with every rocket he owns. 

At this point, it becomes clear the demons aren't going to stop coming ... unless someone cuts them off at the root, that is. Faced with this, the Marine makes the ultimate sacrifice. He closes the portal from the Hell side, remaining there to ensure no demon ever gets it through its thick, viscous brain meats to set foot on Earth again.

At this point, the story and timeline get a bit murky. The Marine's next exploits take place in Hell, recorded by demons with a flair for the dramatic. But there's a few hard facts gleaned from the codex known in-game as the Slayer's Testament. 

The Marine kills with extreme prejudice right away, lasting for eons in Hell time. This earns him a few perks, with a being called Seraphim granting him "terrible power and speed." This upgrade accounts for how the dude rips demons apart with his hands later. He also receives some Hell-forged armor upgrades and the ability to "draw strength from his fallen foes," which might explain why he no longer requires first aid kits.

Most importantly, the Marine gains a hardcore new moniker: the Doom Slayer. After eons of killing, though, the Slayer was bound to make a mistake: he follows a demon into a temple where the priests promptly drop the entire thing on his head. This incapacitates him just long enough to separate him from his suit, seal his body in a sarcophagus, and mark it with a warning to all of Hell that he should never be released.

At some point in the future, the UAC, under the new management of a cyborg named Samuel Hayden, manages to crack the whole teleportation business once and for all. Hayden runs research trips to study demons and artifacts and harnesses Hell's power to solve an energy crisis back on Earth. It's not the brightest idea, but one of the trips leads to Hayden finding the Doom Slayer's sarcophagus and bringing it to his facility on Mars.

Unfortunately, one of Hayden's scientists, Olivia Pierce, ends up under the demons' thrall. She opens a portal, allowing the demons to flood through en masse, killing almost everyone. In his desperation, Hayden lets the Doom Slayer off the chain, unsealing his sarcophagus and offering a brief rundown, one the Doom Slayer doesn't need to hear. The man knows exactly what he's doing.

The Slayer developes a sort of working relationship with Hayden over time, one that's just enough to keep his facility from falling apart. Hayden installs a tether device on the Slayer, allowing him to travel back and forth to Hell without relying on Hell's crappy transit system. However, given a choice between priceless scientific research and an object that lets him tear more demons apart, the Slayer chooses the latter. 

After reaching Pierce's office, the full plan comes to light. Pierce discovered an artifact called the Crucible, a literal Hellblade (no, not that Hellblade) capable of absorbing incredible amounts of energy. Enough to slay legions of demons with a flick of the wrist or open a permanent portal in and out of Hell. After dealing with a new and improved Cyberdemon and two Hell Guards, the Slayer manages to claim the Crucible for himself. 

After using the Crucible to destroy the power sources keeping the portals open, the Slayer returns to Hell and confronts Pierce, whose grand prize for doing Hell's bidding is apparently being turned into the next iteration of Spiderdemon. After introducing her to the business end of his BFG 9000, what should be a hero's welcome turns into a betrayal. Hayden takes the Crucible for himself to continue his research and uses the Slayer's tether to transport him to an unknown location, setting the stage for Doom Eternal.

Doom Eternal takes place years after the events of the 2016 Doom reboot. The Doom Slayer arrives back on Earth to find the planet at the mercy of the now corrupt UAC. Demons have wiped out 60% of the population and the remnants of humanity have either fled or joined the ARC, a flagging resistance movement.

To stop the demonic invasion, the Doom Slayer must find and eliminates three Hell Priests in the service of the Khan Maykr, an angelic creature bent on resurrecting the Icon of Sin and sacrificing mankind. As the Doom Slayer moves towards his goal, he discovers the Khan Maykr allied with Hell, offering the demonic host worlds to invade in exchange for a share of Argent energy. This energy, which the Maykrs need to preserve their people and homeland, is harvested by mass sacrificing human souls.

After eliminating the Hell Priests, the Slayer travels to Urdark, the Maykr dimension, and interrupts the Icon of Sin's awakening ceremony. Freed from the Khan Maykr's control, the Icon of Sin teleports to Earth. The Slayer fights and defeats the Khan Maykr before returning to Earth to face the Icon of Sin in a final boss fight.