Well a lot of it is in small details of how she thinks so i won't be able to translate that but plot tl;dr incoming anyway
One of the major characters of the book is elf Briala who was a daughter of the servants in Celene's noble house or whatever they called it. They practically grew up together and had developed a close friendship. It's heavily hinted however that Celene being human and Briala being an elf it was a somewhat abusive relationship until some point. When Celene hit 16 her parents died because of some court intrigue, very tragic. She took a Grand Old Lady Manipulator of the Orlesian court as her mentor and somehow managed to get rid of the then emperor and take his place, but Briala's parents were killed supposedly by some rival noble.
Anyway Celene became an empress and Briala became her first maid and they got into a romantic relationship (with crushing lips and all of course) and maintained it for a very long time. Briala used her influence to make Celene slowly give elves more rights and freedoms and i guess it was working out pretty well for her, except we keep seeing Celene thinking of elves as some dullwitted cattle that she as a human savior must struggle to uplift. Such an underhanded elf rights campaign.
The coup starts with an uprising in an alienage over a human noble killing an innocent man and hanging his body parts all over the place as a lesson. So Briala tries to quietly lead the local elves to murder the noble in question so that the situation doesn't get more violent, but Celene gets manipulated into burning down the entire alienage to avoid losing the support of the nobles who aren't too fond of the elves. Briala gets arrested everything is very sad blah blah.
Through their next adventures Celene continues to be very reasonable about what happened and spectacularly fails at empathy. In the end Briala finds out that it was actually the empress who ordered her parents killed because they might have overheard Celene's plotting against the former emperor. Very invigorating.
And through this whole gross dynamic Celene just keps being condescending and manipulative and really not a good person. I was actually very happy with the ending because Briala really one-upped her and got a cool powerful thing i'm too lazy to type about.