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.
Alternate Character Interpretation: The Night Lords are either deranged psychopaths who live only to sate their appetite for terror and destruction or misunderstood anti-heroes who fight against the corrupting influence of Chaos while simultaneously extracting revenge on the Imperium which abandoned them. Both interpretations are equally valid in the present and no one fully remembers what the Night Haunter was like or the extent of his original vision.
Zso Sahaal is also shown in two different lights. He is either a tenacious hero trying to keep the remnants of the legion sane by uniting them under him, or is a deranged and naive idiot with an inflated sense of self-importance. Notably, the second interpretation is how the narrator of the Soul Hunter series, Talos, views him; while the first is how many fans of Lord of the Night see him, as well as Mercutian and Uzas. Talos himself also can be seen in a less extreme version of either interpretation.
Konrad Curze heavily invokes this. Did he champion "order through fear" as a means of ensuring justice yet reject Chaos itself at the same time as joining Horus, like Sahaal and Talos claim? Was he as thoroughly corrupted as the other Traitor Primarchs and desired his sons to feed on fear like Acerbus claims? Or was he just a broken maniac like Xarl and Lucoryphus claim? No two Night Lords can seem to agree on what Curze wanted.
Ensemble Darkhorse: For how little screen/page time Sevatar has received in canon, Aaron Dembski-Bowden receives an awful lot of questions about him.
Fridge Horror: Towards the end of Lord of the Night Mita throws a psychic blast far stronger than anything else she's ever done with little effort, leading her to conclude that her psychic power is not the Emperor's grace and is not the Warp's randomness, but "is her own". Thinking this thought is a good way to get the entire Warp pissed at you.
Rescued from the Scrappy Heap: Whilst they were not exactly hated, the Night Lords received remarkably little coverage in either background or rules prior to the publishing of Lord of the Night.
Ultramarines players love Aaron Dembski-Bowden's handling of their chapter.