I've seen plenty of people who do not understand the story of Darkest Dungeon 2. And I've yet to see a video that covers all the Academic's quotes that explain the story. Hopefully, this will solve both of these issues.
To clarify for those still unsure of the story, or just simply don't have enough time to watch this video:
The Narrator is referred to as the Academic. You, the player, are referred to as the protégé.
You were the Academic's brightest student, and you shared many anthropological interests. It was you who found the equation that would unravel the world - the "Iron Crown", a semi-circle with five points of power. The symbol itself was pervasive throughout all of human history, found in the emblems of every civilization.
You continued researching this long-forgotten symbol, but the Academic worried about you. You were adamant about revealing this secret to the world - but the Academic rebuffed your desire, breeding resentment in you.
Eventually, the Great Library you researched the Iron Crown in burnt down, much to the Academic's relief. However, you both received a letter from a mysterious man (The Ancestor from the first game), inviting you to his manor. There, you met with his cabal of devotees that were also obsessed with the Iron Crown. Per the Academic's insistence, you retired to your room that night. Upon waking, you both found the corpses of the cabal members lying on a semi-circle on the floor. The five bodies represented the five points of power, just like the Iron Crown. The Academic was disgusted, but you grew obsessed with this ritual.
Persistent to unravel the mystery of the symbol, you implored the Academic to help you with your research in your home. You enacted many horrific rituals that reshaped you and repulsed the Academic. Eventually, he grew tired of your unbridled ambition and readied himself to leave. But, before he could, you lured him into your cellar. There, he saw what you had done; you planted four corpses around a semi-circle. As you drove your dagger through his chest, he realized he was to be the fifth point of power.
The world forever changed from that moment, as the calculation of the Iron Crown was realized by you. The equation imprinted your sinful mind upon the world, reshaping it into the wasteland of failure and regret you see in the game. Upon seeing the wretched horrors you wrought, you fled to your house in the Valley. That is, until you were stirred by the memory of the Academic, who implored you to set out and make things right. Giving you your last glimmer of hope still present in your soul, you and four heroes travel through the world and help you confess to your five, grand mistakes - Denial, Resentment, Obsession, Ambition, and Cowardice. All the while, the heroes themselves reconcile with their past and look to redeem themselves in the present.
In the end, the heroes kill you and your Body of Work, but the world will be reborn from the more wholesome memories you kept of it. The cosmic axes are re-aligned and hope is restored. The heroes set out to help the survivors of this world and rebuild it with them.
Chapters:
0:00 Opening
0:11 Intro Cinematic
2:00 Prologue
2:20 Denial, Introduction
2:59 Denial, Additional Lore
4:26 Denial, Boss
4:50 Denial, Conclusion
5:41 Resentment, Introduction
6:18 Resentment, Additional Lore
7:39 Resentment, Boss
8:04 Resentment, Conclusion
8:38 Obsession, Introduction
9:10 Obsession, Additional Lore
10:57 Obsession, Boss
11:22 Obsession, Conclusion
12:01 Ambition, Introduction
12:44 Ambition, Additional Lore
14:31 Ambition, Boss
14:57 Ambition, Conclusion
15:40 Cowardice, Introduction
16:23 Cowardice, Additional Lore
17:44 Cowardice, Mountain Approach
19:13 Cowardice, Boss Introduction
19:37 Cowardice, Boss Phases
20:24 Exultations
21:22 Cowardice, Boss Killed
21:40 Ending Cinematic
22:51 The End