Same here. I hate it when authors give them just a slap on a wrist especially if they're women. But the author went through the trouble of giving her a just motive a.k.a the "not wanting second prince ascend throne because his main backer Duke Clockford wants to invade Landor and she doesn't want that because her grandma was from Landor and they owe them big time in saving them from dragon attacks when it should have been the Kingdom's duty to do so".
Regicide may be a capital offense but the Kingdom also shares the blame for their inability to properly aid and protect Casey's territory so I'd be more willing to give Casey some slack with this one.
I genuinely love the fact that the characters in Secrets of the Silent Witch are complicated in very humanizing ways. Casey is being driven by grief and anger into doing something she KNOWS is wrong, deep down, but feels like if she doesn't try to do SOMETHING, things will only get worse. And when it all unravels she tries everything to push Monica away in order to protect her from getting any more hurt than she already is.
Felix is capable of putting on a friendly face and saying all the right things to charm the pants off of everyone around him, but in the brief flashes we see of him alone we also get a glimpse of a darker personality that lurks behind his perfect, princely smile. He casually schemes about trying to manipulate Monica into relying on him by having others bully her so he can step in and play the hero, but then in the next moment we see him being a lovesick fanboy swooning over his crush on the Silent Witch.
Elliot is an elitist asshat 90% of the time, but he tries to protect Monica from a couple of thugs wielding knives even though he has NO combat abilities, because it's the duty of nobles to defend and protect the common folk. Cyril comes across as strict and hot tempered, but is also hard working and kind to a fault. Hell, even Louis. He looks like a perfect gentleman, then acts like a common thug, but he's also strangely conscious of Monica. Despite how he usually treats her he has an incredible amount of respect for her skills even though she's ten years younger than him, and him lending her the handkerchief that his darling Rosalie gifted him shows that he does care about her a lot more than he's willing to show.