Darkest Dungeon 2 is a story told by the Academic, the player character's former mentor. At first, you don't receive much in the way of details, only having a quest to save the world thrust upon you as if from nowhere. As you work your way through the game, though, you'll discover that there is much more to the Spreading Stain and its origins than you might have guessed.
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If you need a refresher on the plot of Darkest Dungeon 2, or just want to know what happens without battling the game's challenging bosses, read on... if you dare.
This article contains major spoilers for Darkest Dungeon 2.
Whenever you start a new expedition in Darkest Dungeon 2, the player character signs their written confession with the name "Reus Captivus." This is Latin for "accused prisoner," so it's unlikely that this is the protagonist's actual name. However, it's the only name by which they're ever referred, so we'll use it for the purposes of identifying them.
A student of anthropology, Captivus enrolled in a prestigious university. Considering that the game's world is evocative of 17th-century Europe, this suggests that they came from a well-off background that afforded them the luxury of scholarship. Captivus' excellent marks and inquisitive nature caught the attention of one of their professors, the Academic.
The Academic took Captivus as his protégé, involving the young student in his research and helping them find opportunities to make their name known. As the semesters wore on, the two became close friends and would spend summers together discussing esoteric and arcane mythology, a subject that interested them both but was looked down upon by the university.
Conducting their summer research at a remote cabin in a valley at the kingdom's border, Captivus and the Academic discovered a strange and potentially history-making pattern. A symbol they called the Iron Crown - a semicircle intersected by five lines - appeared somewhere in the mythos of every ancient culture known to history, regardless of geography, religion, or societal values. Given the Iron Crown's association with forbidden knowledge and the occult, this could point to a greater force influencing humanity and leaving its mark.
Captivus wanted to publish the pair's findings right away, believing that such a discovery would immediately make them a celebrated anthropologist. The Academic, however, insisted that they keep their research secret until they had concrete, incontrovertible proof that the Iron Crown was more than just a coincidence. Seeing that Captivus was undeterred, the Academic pulled rank and demanded that his student keep the discovery a secret.
Resentfully continuing their research in secret, Captivus planned to visit the Great Library, the largest repository of ancient knowledge in the known world. To Captivus' dismay, just before the journey a fire in the Library destroyed the texts they had hoped to see. Soon after the blaze, both Captivus and the Academic received an unmarked envelope with the symbol of the Iron Crown.
The pair were invited to a gathering of scholars with similar interests, at a mansion on a sprawling estate. It's possible - though not confirmed - that this is the mansion from the first Darkest Dungeon game. Hooded and masked, the scholars treated Captivus and the Academic to a feast while trying to learn what the two had discovered about the Iron Crown and its significance.
The Academic suspected that their hosts were interested in more than simple research, and was quickly proven correct when the group started drawing ritual circles and lighting candles. Captivus wanted to stay and witness the arcane rite, but the Academic took his student to their room and barricaded the door, waiting out the night.
In the morning, the pair emerged to discover a grisly scene - five dead scholars, their bodies hanging from an arch in the configuration of the Iron Crown. The owner of the house and leader of the cabal, had vanished. The Academic was horrified, but Captivus was enthralled.
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Captivus dropped out of the university, taking up residence in the mansion and using the resources left behind by the cabal to relentlessly pursue the secrets of the Iron Crown. They invited the Academic to join them, and he reluctantly agreed, hoping he could talk some sense into his student, who had become his closest friend.
Captivus believed that the celebrants had performed the Rite of the Iron Crown incorrectly, and sought to fully unlock its secrets. Without the Academic's knowledge, Captivus abducted and killed four people to serve as sacrifices. Finally, they showed the Academic their work, stabbing their horrified mentor in the back and making him the fifth and final offering to the Iron Crown.
The Rite worked, tearing open a gateway to another dimension. The Iron Crown imprinted Captivus' mind onto reality itself, manifesting all of their fears, doubts, and loathing as physical beings. Across the globe, otherworldly entities sprang forth from holes in the fabric of reality. Many people were killed, and most that survived were driven to acts of violence and depravity.
In the cities, people were taken with religious fervor, believing that human knowledge had brought divine judgment. These Fanatics set about burning books, buildings, and themselves. In rural farmlands ruled over by feudal lords, crops withered overnight and animals died; the nobility turned to cannibalism to keep themselves alive.
At the shores, sunken monoliths sprang up from the ocean floor and slumbering monsters emerged from the waves. The inhabitants of coastal fishing villages took to worshiping these monsters and began to transform into human-fish hybrids; and in forgotten places long considered cursed, the dead began to stir.
Captivus saw what they had done, and it broke them inside. Fleeing to the cabin in the valley, Captivus shut themself inside and tried to block out the terror that was engulfing the world. It is unknown how long Captivus stayed in their self-made prison, but eventually they were able to convince themself that they had nothing to do with the coming apocalypse, willfully forgetting everything that had happened.
Captivus' exile was eventually interrupted by a figure knocking down the door to the cabin; the Academic, now an undead husk, came bearing a burning flame. Resurrected by Captivus' memories of the time before the incident, the Academic made a final effort to save his friend - and the world.
Without reminding Captivus of the events in the mansion, the Academic explained that the Flame of Hope could restore the world if it was brought to the Temple of the Iron Crown atop a faraway mountain. The two loaded their stagecoach and, at a nearby crossroads, recruited help from adventurers who had survived thus far. These heroes were all running from their own past, making them kindred spirits to Captivus in more ways than they knew.
The party made its way through the benighted world, fighting off the Spreading Stain and those it had corrupted, while offering aid to whatever survivors they found to keep the Flame of Hope burning. Their way to the Mountain was barred by enormous avatars of the Iron Crown - the Shackles of Denial, the Seething Sigh, the Focused Fault, and the Ravenous Reach. Unknown to Captivus, these were all incarnations of their own self-loathing, brought to life by the Iron Crown.
As each Guardian fell, Captivus was able to remember more of the memories they had repressed, and - guided by the Academic's kind but stern words - accept and take responsibility for what they had done. At the Temple of the Iron Crown, which had sprung up from the mansion where the Rite had taken place, Captivus led the heroes to battle the evil god that had taken shape from their own failings and hatred.
One by one, the heroes learned to accept their past and the scars it had left, freeing themselves from the crushing weight of the Iron Crown. As the final blow was struck, the Academic revealed that killing the Crown's manifestation would result in Captivus' death as well, but the world would be rebuilt from the youth's memories, much like the Trinkets that the party had found along the way.
After Captivus' death, their companions set about providing aid to the survivors and reconstructing destroyed cities, their faith and energy renewed. Though it's not explicitly stated, it is likely that the Academic died at the same time as Captivus, having fulfilled his purpose.
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