Complete story — includes the ending
=== Main campaign ===
In 2163, fourteen years after the events on Mars, Earth has been overrun by demons, wiping out 60% of the planet's population. The Union Aerospace Corporation (UAC) has been fully corrupted into a demonic cult. What remains of humanity has either fled Earth or joined the Armored Response Coalition (ARC) resistance movement. The Doom Slayer, having previously been betrayed by Dr. Samuel Hayden, returns with a satellite fortress controlled by the AI VEGA to quell the demonic invasion by killing the Hell Priests: Deags Nilox, Ranak, and Grav. The priests serve an angelic being known as the Khan Maykr, who seeks to sacrifice mankind for her own race's survival. The Slayer teleports to Earth and kills Deag Nilox, but the Khan Maykr transports the two remaining priests to unknown locations.
The Slayer retrieves a celestial locator from the Sentinel city of Exultia, and then travels to Hell to acquire a power source from the exiled Sentinel, the Betrayer. The Betrayer also gives him a dagger to stab the heart of his son, whose body was turned into the apocalyptic demon, the Icon of Sin. The Slayer finds and kills Deag Ranak at his citadel in the Arctic. In response, the Khan Maykr moves Deag Grav again and accelerates the invasion of Earth. With no leads on the last Hell Priest, VEGA suggests finding Dr. Hayden, who knows his location. At an ARC compound, the Slayer retrieves Hayden's damaged robot chassis and the demonic Crucible.
Upon uploading Hayden's mind into the fortress, he reveals Deag Grav is hiding on Sentinel Prime; the only way to get there is a portal located in the lost city of Hebeth in Mars' core. The Slayer travels to the Martian moon Phobos, where he uses the BFG 10000 to shoot a hole in the surface of Mars to reach Hebeth. After reaching Sentinel Prime, flashbacks reveal the Slayer to be the original Doomguy. Found badly wounded by Sentinels sometime after Doom 64, Doomguy was brought before the Deags and forced to fight in a gladiatorial arena. Impressed by Doomguy's ruthlessness in battle, the Deags inducted him into the Sentinels.
In the present, the Slayer finds and kills Deag Grav in the arena. The Khan Maykr reveals to the Slayer her plan to resurrect the Icon of Sin to consume mankind. The Slayer travels to the Sentinel homeworld of Argent D'Nur for his own Crucible. Further flashbacks reveal that during the battle of Argent D'Nur, a rogue Maykr called the Seraphim imbued Doomguy with superhuman abilities by putting him in the Divinity Machine, transforming him into the Doom Slayer. It is revealed that the Khan Maykr had made a pact with Hell to produce Argent energy, which is created through the mass sacrifice of human souls. In return for providing worlds for Hell to invade, the Maykrs receive a share of the Argent energy produced by Hell, which allows their own dimension, Urdak, to survive.
The Slayer enters Urdak through Hell's citadel, Nekravol, and halts the Icon's awakening ceremony by using the Betrayer's dagger to destroy its heart. Free from Maykr control, the Icon of Sin awakens and teleports to Earth. With the dimensional barrier destroyed, the demons break their alliance with the Maykrs and invade Urdak. The Slayer kills the Khan Maykr before returning to Earth to confront the Icon of Sin, although VEGA is left behind to ensure the portal stays open and in doing so, learns that he is the mind of the Father, the creator of the Maykr race. The Slayer kills the Icon of Sin in battle, ending Hell's invasion of Earth.
The Ancient Gods
==== Part One ====
Despite defeating the Icon of Sin and halting Hell's invasion of Earth, the Doom Slayer's victory did not come without cost. The death of the Khan Maykr and Hell's conquest of Urdak has given the demons a chance to dominate all dimensions and reinitiate their invasion of Earth. To prevent this, the Slayer, Samuel Hayden, and ARC scientists set out to liberate the Seraphim. The Slayer travels to the UAC Atlantica Facility, where the Seraphim's containment pod is. He uploads Hayden's consciousness into the pod, and it is revealed that he and the Seraphim are one and the same.
The Seraphim, suffering from a transfiguration terminal illness, tasks the Slayer with retrieving the Father's Life Sphere from the Blood Swamps of Hell, located within the Ingmore's Sanctum, in order to combine it with VEGA and return the Father to physical form. The Slayer finds the sphere but chooses to destroy it rather than hand it to the Seraphim, and instead retrieves the Dark Lord's Life Sphere with the intent of resurrecting and then destroying him, which in turn will destroy all demons outside of Hell.
The Slayer returns to Urdak, which has been corrupted by the demons' occupation and reaches the Luminarium, which anyone with a Life Sphere may activate. However, the Slayer is confronted by the Seraphim, consumed by the degenerative transfiguration, and defeats him before the Father teleports him away. Despite being warned that bringing the Dark Lord into physical form is irreversible, the Slayer proceeds to summon him, only to be confronted with a being who is a mirror image of him.
Part Two
Having summoned the Dark Lord into existence, the Doom Slayer attempts to kill him but fails, as blood cannot be shed in the Luminarium. The Dark Lord tells the Slayer he will be waiting for him in Hell's capital city of Immora. To reach Immora, the Father informs the Slayer that he must activate the Gate of Divum, the only portal capable of reaching the city. The Slayer goes to Argent D'nur for a Wraith Crystal to power the portal, located inside the World Spear, a massive crystalline alien ship that had impaled the planet long ago (hence it "spearing" the world). On the way, the Slayer encounters the Betrayer, who has reassumed his original name, Valen, after the defeat of the Icon of Sin. The Slayer lights the Torch of Kings to rally the remaining uncorrupted Sentinel forces, then recovers the Wraith Crystal.
The Slayer activates the Gate of Divum on Earth. Traveling to Immora, the Slayer is greeted by the city's formidable defenses consisting of a massive wall and an army of demons. He is assisted by an army of Sentinels led by Valen and many of the remaining human forces, who teleport in and assault the city. While Hell's main forces are occupied with them, the Slayer follows the Dark Lord.
After fighting through Immora and being teleported to an arena, the Dark Lord and the Slayer fight. The Dark Lord reveals that he was the true creator of the multiverse and that Jekkad (later known as Hell) was the first dimension. The Maykrs, including the Father, betrayed him and rewrote history to depict the Father as the first being. This led the enraged Dark Lord to influence Samur Maykr to turn Doomguy into the Doom Slayer, whose original purpose was to (unintentionally) contribute to the destruction of the Maykrs and the Father, fulfilling the Dark Lord's revenge. The Slayer kills the Dark Lord, and all demons outside of Hell are instantly destroyed with his death, stopping the invasion for good and saving humanity and all other forms of life across the multiverse. Being one of the Dark Lord's creations himself, the Slayer falls unconscious before being sealed inside a stone sarcophagus at the Ingmore's Sanctum by the Seraphs until he is needed again.
In 2163, fourteen years after the events on Mars, Earth has been overrun by demons, wiping out 60% of the planet's population. The Union Aerospace Corporation (UAC) has been fully corrupted into a demonic cult. What remains of humanity has either fled Earth or joined the Armored Response Coalition (ARC) resistance movement. The Doom Slayer, having previously been betrayed by Dr. Samuel Hayden, returns with a satellite fortress controlled by the AI VEGA to quell the demonic invasion by killing the Hell Priests: Deags Nilox, Ranak, and Grav. The priests serve an angelic being known as the Khan Maykr, who seeks to sacrifice mankind for her own race's survival. The Slayer teleports to Earth and kills Deag Nilox, but the Khan Maykr transports the two remaining priests to unknown locations.
The Slayer retrieves a celestial locator from the Sentinel city of Exultia, and then travels to Hell to acquire a power source from the exiled Sentinel, the Betrayer. The Betrayer also gives him a dagger to stab the heart of his son, whose body was turned into the apocalyptic demon, the Icon of Sin. The Slayer finds and kills Deag Ranak at his citadel in the Arctic. In response, the Khan Maykr moves Deag Grav again and accelerates the invasion of Earth. With no leads on the last Hell Priest, VEGA suggests finding Dr. Hayden, who knows his location. At an ARC compound, the Slayer retrieves Hayden's damaged robot chassis and the demonic Crucible.
Upon uploading Hayden's mind into the fortress, he reveals Deag Grav is hiding on Sentinel Prime; the only way to get there is a portal located in the lost city of Hebeth in Mars' core. The Slayer travels to the Martian moon Phobos, where he uses the BFG 10000 to shoot a hole in the surface of Mars to reach Hebeth. After reaching Sentinel Prime, flashbacks reveal the Slayer to be the original Doomguy. Found badly wounded by Sentinels sometime after Doom 64, Doomguy was brought before the Deags and forced to fight in a gladiatorial arena. Impressed by Doomguy's ruthlessness in battle, the Deags inducted him into the Sentinels.
In the present, the Slayer finds and kills Deag Grav in the arena. The Khan Maykr reveals to the Slayer her plan to resurrect the Icon of Sin to consume mankind. The Slayer travels to the Sentinel homeworld of Argent D'Nur for his own Crucible. Further flashbacks reveal that during the battle of Argent D'Nur, a rogue Maykr called the Seraphim imbued Doomguy with superhuman abilities by putting him in the Divinity Machine, transforming him into the Doom Slayer. It is revealed that the Khan Maykr had made a pact with Hell to produce Argent energy, which is created through the mass sacrifice of human souls. In return for providing worlds for Hell to invade, the Maykrs receive a share of the Argent energy produced by Hell, which allows their own dimension, Urdak, to survive.
The Slayer enters Urdak through Hell's citadel, Nekravol, and halts the Icon's awakening ceremony by using the Betrayer's dagger to destroy its heart. Free from Maykr control, the Icon of Sin awakens and teleports to Earth. With the dimensional barrier destroyed, the demons break their alliance with the Maykrs and invade Urdak. The Slayer kills the Khan Maykr before returning to Earth to confront the Icon of Sin, although VEGA is left behind to ensure the portal stays open and in doing so, learns that he is the mind of the Father, the creator of the Maykr race. The Slayer kills the Icon of Sin in battle, ending Hell's invasion of Earth.
The Ancient Gods
==== Part One ====
Despite defeating the Icon of Sin and halting Hell's invasion of Earth, the Doom Slayer's victory did not come without cost. The death of the Khan Maykr and Hell's conquest of Urdak has given the demons a chance to dominate all dimensions and reinitiate their invasion of Earth. To prevent this, the Slayer, Samuel Hayden, and ARC scientists set out to liberate the Seraphim. The Slayer travels to the UAC Atlantica Facility, where the Seraphim's containment pod is. He uploads Hayden's consciousness into the pod, and it is revealed that he and the Seraphim are one and the same.
The Seraphim, suffering from a transfiguration terminal illness, tasks the Slayer with retrieving the Father's Life Sphere from the Blood Swamps of Hell, located within the Ingmore's Sanctum, in order to combine it with VEGA and return the Father to physical form. The Slayer finds the sphere but chooses to destroy it rather than hand it to the Seraphim, and instead retrieves the Dark Lord's Life Sphere with the intent of resurrecting and then destroying him, which in turn will destroy all demons outside of Hell.
The Slayer returns to Urdak, which has been corrupted by the demons' occupation and reaches the Luminarium, which anyone with a Life Sphere may activate. However, the Slayer is confronted by the Seraphim, consumed by the degenerative transfiguration, and defeats him before the Father teleports him away. Despite being warned that bringing the Dark Lord into physical form is irreversible, the Slayer proceeds to summon him, only to be confronted with a being who is a mirror image of him.
Part Two
Having summoned the Dark Lord into existence, the Doom Slayer attempts to kill him but fails, as blood cannot be shed in the Luminarium. The Dark Lord tells the Slayer he will be waiting for him in Hell's capital city of Immora. To reach Immora, the Father informs the Slayer that he must activate the Gate of Divum, the only portal capable of reaching the city. The Slayer goes to Argent D'nur for a Wraith Crystal to power the portal, located inside the World Spear, a massive crystalline alien ship that had impaled the planet long ago (hence it "spearing" the world). On the way, the Slayer encounters the Betrayer, who has reassumed his original name, Valen, after the defeat of the Icon of Sin. The Slayer lights the Torch of Kings to rally the remaining uncorrupted Sentinel forces, then recovers the Wraith Crystal.
The Slayer activates the Gate of Divum on Earth. Traveling to Immora, the Slayer is greeted by the city's formidable defenses consisting of a massive wall and an army of demons. He is assisted by an army of Sentinels led by Valen and many of the remaining human forces, who teleport in and assault the city. While Hell's main forces are occupied with them, the Slayer follows the Dark Lord.
After fighting through Immora and being teleported to an arena, the Dark Lord and the Slayer fight. The Dark Lord reveals that he was the true creator of the multiverse and that Jekkad (later known as Hell) was the first dimension. The Maykrs, including the Father, betrayed him and rewrote history to depict the Father as the first being. This led the enraged Dark Lord to influence Samur Maykr to turn Doomguy into the Doom Slayer, whose original purpose was to (unintentionally) contribute to the destruction of the Maykrs and the Father, fulfilling the Dark Lord's revenge. The Slayer kills the Dark Lord, and all demons outside of Hell are instantly destroyed with his death, stopping the invasion for good and saving humanity and all other forms of life across the multiverse. Being one of the Dark Lord's creations himself, the Slayer falls unconscious before being sealed inside a stone sarcophagus at the Ingmore's Sanctum by the Seraphs until he is needed again.
Sources and content license
Source and revision history ↗ · Adapted from Wikipedia contributors, Doom Eternal. HTML and reference formatting removed; headings adjusted. · Content license