These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Halo: Cryptum
Crowning Moment of Funny: Chakas asks if he can sleep with his Ancilla (AI). Bornstellar's snarks that he'd like to see him try. One wonders what the Ancilla, who is right there, made of it.
The Didactfreaks when he's told their former enemies tend to his comrade's graves. Bornstellar inches away, since he "seemed to be looking for something to pick up and throw".
Chakas and Riser ask Didact some uncomfortable questions, like how many humans he's killed. His response? Lock them in a room with some food.
Tearjerker: Several. Most prominently, Bornstellar succumbing to the Didact's personality. He spends much of the last half of the book wondering if he'll be able to retain anything of his original self, but in the end, he's gone.
Bornstellar's (in narration) thoughts as he leaves his family's home. He comments that he wishes he could forget the last days he spent there, because they only bring him pain: it was the last time he ever saw his family again. Fridge Horror, since we all know what attacked the Forerunners soon after.
The whole of the Didact's story. Forced to mutate before he was ready, participated in a war he now knows was pointless, every one of his children dead, forced into exile for a thousand years, away from his beloved wife, and in the end, he never sees her again: he's tortured and executed by the Master Builder.
The last part somewhat subverted, though: he's still alive somewhere. Stranded in a Flood-infected system.