
So,
1.
The assassins during the ball wasn't set up by the princess, but was actually meant FOR the princess, BY the prince faction. MC unintentionally thwarted a plan that could've ended the brat's madness
2.
The prince faction instead, decided to have the brat fall from grace. BUT, I have a few questions:
2.1
Why do they need Shirley as a scape goat /have her killed?
They could've just added her detainment as another reason for the brat's madness and ineligibility to rule. Will the cons of having Reius and Gimmy(?) become an enemy outweight the pros of such endeavours?
If Caid puts his mind to it, he can start a rebellion (I hope).
2.2
Assuming the faction's reach in the palace is deep, why not set up another band of assassins to kill the princess?
Because they can't think of a way to make it untraceable to the prince? (Ie his eligibility decreases if he's incriminated in the death of the princess)
2.3
Given the amount of damage the brat did to them, why maintain MC and co as enemies? Wouldn't if be more helpful for the deluded faction to have them as allies, esp when after the brat is out of the picture?
2.4
If they were aware of her madness, why empower her at all???
2.5
Exactly how do they think the prince will take this in after everything?
What if the prince discovered everything and found a way to pass the throne to someone else, out of guilt?
3.
This arc better have sufficient story significance. It better not be this tragic just to put its audience and main cast through the wringer. (PLEASE. It's a really good story so far, please keep it so.)

Some theories:
2.1. Unfortunately, Shirley is detained over valid (if false) pretenses. She's currently being investigated for the king's murder. My assumption is that Prince Marsh's faction want to expose the princess as the murderer AFTER she's taken an innocent life, therefore cementing her as a tyrant who needs to be removed from the throne.
2.1.1. There's also no way Caid would rebel knowing that Shirley is still alive and the princess could just kill her in retaliation. That might also be part of the reason Shirley "needs to" die, so that Caid has nothing holding him back and he can blindly side with the revolution. It's the same logic they employed when thinking that Ezador "had to" die for Caid to return to Reius (although he only did so because of Shirley's guilt, not his own).
2.2. Most likely, yes. I also think part of it has to do with Prince Marsh's ability as a leader, although this is purely conjecture. While the king were alive he would still keep the crown, so murdering the princess would put the prince in a position of questionable authority but still give time to earn his right on the throne until the king's natural passing. With the king dead, however, there's a chance that killing the princess just leads to a power vacuum that the other nobility (non-prince faction) will struggle over. Call the princess a tyrant and put the prince (unwillingly?) at the helm of the whole revolution, however....it's the same situation that Caid himself was in, and he has unequivocal control over Reius.
2.3. Noble politics is like 5d chess with multiversal time travel, so I really don't know here. My best guess would be that, at the end of the day, the prince's faction doesn't actually care about the prince or anybody around him, they only care about results, and this might be the plan with the 'best' results (also they already killed Ezador to get Caid to go back to Reius, so there's a non-zero chance Caid just tells them to go to hell if he finds out).
2.4. Because everybody else already drank the princess kool-aid. The ones who wanted to remove her were already trying, but the princess herself says over and over that she's so loved that she deserves and more or less gets everything she wants (Caid notwithstanding), which is gross but also something a very successful cult leader can say.
2.5. At this point, the prince's faction is probably just the anti-princess faction. It definitely sounds like they don't give a shit about his feelings and only want him in the throne because he's the lesser of two evils. Once he's in the throne, I'm sure any of his supporters would gladly take the crown from him given the chance.

Not "why are you thinking that way, that's wrong/weird!"
- outright denial / criticism of fear
Not empty words of "that's okay, just believe that it's going to be okay"
- surface level validation and/or groundless faith
But ACTUAL ACTIONS to address that fear / anxiety
- what can we do to prevent its fruition/ deal with its consequences
NOTE
I am aware such a response isn't always feasible or productive. But in such situations, I find it much more helpful.

I mean, I can understand using whatever reason in order to meet him and talk to him again, however briefly.
But to not realize/suspect that he's in a rut?
Even other oblivious beta I've read about weren't that bad.
Was he living under a rock?
.
Then again, he did have absolute faith in his beta-ness.
Guess he didn't expect to fall victim to the heat
Maybe he didn't think the consequences will be that bad (since he thought he wasn't omega)
Doesn't make it "right" though

True. But given that perhaps he's never seen anyone in heat or rut his entire life either this society has very good grip on their pheromones regulation and heat and rut cycle suppressance then I guess he wouldn't have had first hand experience seeing an omega or an alpha in heat, lack of ability to sense pheromones notwithstanding. I'm assuming he hasn't even seen a close -one/friend/family member going into heat? A neighbor, some random dude, idk. Was he THAT sheltered?!? I mean symptoms other than the glaringly obvious pheromone detection for alphas and omegas. If sex Ed was somehow lacking and didn't give any video demo or textbook examples....I mean, the cluelness is a bit extreme.
Granted, personally he himself has been, as someone else has said, into his beta-ness so much never involved himself in anything else.

I think this goes on the premise that betas make up the vast majority of society. But I agree, I don't think it's to do with being sheltered per se - but the obvious lack of appropriate sex education is obvious. I think alot of east asian countries have pretty subpar sex/health education - so with that in mind, the context of this story makes sense.
I work in both mental health and education, I'm telling you these things need to be explicitly taught, otherwise there are gaps in knowledge that have nothing to do with being sheltered haha.

Yeah... Well, my family is Asian and the ONLY sex talk ever had is: 1. No premarital sex or you die a virgin. Yup. And there is no talk of STDs or anything and if you should get pregnant out of wedlock you bring shame to the family. No education on contraceptives, nothing. That's the most dangerous, cuz trying to regulate me by telling me rape stories (yup) gotta thank my mom for being traumatized by sex and feeling guilty about sex ... And being told that women don't have sexual feelings and that women are taught how to have sex by their husbands. Yup yup. Peachy is my life, then being called indirectly a whore cuz then I tried to break the no premarital sex and traumatized for about 5 years before I could let go of the fact that it's her own belief system and no matter how long we've lived in the U.S. that's just how "she" believes I should live. Also, no cohabitation, yup. My sis broke the rules on THAT one. The rape stories traumatized me for at least 10 years. She started out by giving me newspaper clippings since when I was about 12/13/14...

That's horrible I'm so sorry. I can see how that would be traumatising. I think it also shows how traumatised your mum and her peers were, as sex was this awful scary thing that gets done too you, with no body autonomy - because that's what you do when you're married.
I think it's great you'd managed to differentiate those beliefs from your own. I like to reframe to 'I am sorry" to "am I safe?". Am I engaging in safe sexual behaviours? Are they enjoyable? Do I trust this person/s?.
I think its important we detach shame from normal human behaviour (i.e., sex). When we learn what safe behaviour is, we're in a much more empowered position with issues like consent, rape or unwanted pregnancy. If the characters within this story learned anything, they'd absolutely not be in this position.

Please:
Either he gets a HUMONGOUS AND AMAZING chara development
Or
They divorce. She relocates, gets Kanon as disciple/assistant, and sets up shop as a whimsical witch who overtly helps people in need.
It's not like she'll need the count / nobility / money at this point (since she's OP?)
EDIT
Oh man. The last chapter reduces his ML potential by A LOT.
Now, super hoping for option 2 too.

I really love how she's raising them as "modern independent women" without outright disregard nor disrespect for their society's current norms

And i also love how various characters try to terms with her pioneering (for those times) strategies and ideals, coz in most manhwas it's always "everyone except bestie and/or ml shun this woman for tryna think" ykwim? Like some characters superficially accept these ideas (like Casey Jr), some try to come to a compromise with the beliefs they hold and her ideas (the queen mother) and some people agree with her (that countess who was talking about women reading). It's very refreshing that these aren't just generic responses yanno?
For a second, I seriously thought she was going to pimp then out......
She won't right?
no no, she's showing them a potential talents
She wants them to be muses for artists
So then the public views on demons shifts to a more favorable one
nope, her "Emi" wouldn't want that :-))