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.
Andréa/Arthus has serious overtones of this, though given their personalities it's nearer to Foe Romance Subtext.
Orane, wearing nothing but a shirt and some leggings, kneels in front of a naked Yz and tells Andréa and Elwood they need to win each other's love. The day they're able to hold each other, they'll be ready to go back to the World of the Oak.
Moral Event Horizon: In book 5, Rouche leads his faction of ferrets on a genocidal raid against the Transparents. Despite all hints that he was willing to do this all along, it's still definitely brutal. The first thing he does during the raid is to shoot a mother dead in front of her daughter because the woman's warning cries spoiled the element of surprise.