Personally I'm a bit annoyed that prince didn't come earlier to save also MC's subordinates... But I think this is partly for MC to feel more guilty, but it might also be something that prince did, so MC always remember what will happen if he rebels or similar to that... I think this whole story going to be full of red and black flag that fit to the dark art.
Its definitely got the feel of that he is going to be emotionally and mentally used and abused for his previous actions and his consequences.
Ie...killing the king and essentially his men.
It kind of seems like a mix of Roses and Champagne with YUWU.
In which MC held a title that got him to fall in an unfit manner to the lowest of the low to meeting a black flag ML who will use him...and while not love him...definitely perhaps become possessive and sadistic over him.
It gonna be a hell of an angsty ride....
Come on... It not even close to Roses and Champagne. Nobody beat Lee won as an uke, too bad he ended up in that kinda world - but I said this in b2to before... Lee won is the only one who can even come close to handling Caesar so he had to be sacrificed for that job.
Once I saw the mountain pen and said to myself, please do it, and Lee Won did it. I didn't care about black flags around him, I was there just for him.
Maybe this is going to be closer to Legs that won't walk if the ML is black flag? Lee Won was just a lawyer anyway... In Legs that won't walk, MC had an actual title as a poor fighter until he couldn't fight and everyone used him, this seems to be more like that - but medieval version.
...did you fully read C&R ? Lol
Ceaser isnt a black flag for no reason my dude XD its not he like he was so nice and sweet to Leeewon in bed let alone in parts of his life outside of a bedroom...
(Man's literally shot him, and then raped him for days...and it proceeded to drug him and again...rape him...) does this not count as beating!? XD wtf!?
(● ̄(エ) ̄●)

I think we did get quite a lot of info from first two chapters, unless I'm totally wrong:
The knight was ordinally a man/boy whore or something similar... He raised from the bottom to be loyal knight to the king. He really doesn't have any society or nobility level of power, either he is originally from fallen house or basic commoner. Maybe a bastard, but I doubt that, because even bastards often have some status power.
This is me partially guessing from the hints we get only in two chapters. The MC is barely a knight, at least non-noble one and can't actually fight against anyone without backing of a royal or noble - despite his higher rank in an army. It doesn't matter if you are strong knight if you can't hit anyone.
He was tricked by the Duke to be part of rebellion, thinking that Duke has his backing. But he and his men were just scapegoats. And the prince who was sent as a hostage in a another country is disappointed, because he was ready to do the rebellion himself.
I'm not sure how the dead Duke's son knows so well about MCs past (what I suspect is MC being a boy whore etc.)... Maybe Duke family sponsored him so he could get into training to be knight? That would make sense why MC trusted to rebel with the Duke, not just what MC has to do because order of the king.