
Oh no, it hit me how fake Kyung Joon is when he spoke about the wedding. How carefully he's chosen the timing, and that he speaks to Nok always super stricktly formal - that it even makes Nok sad and hurt by it.
Also "the best friend" thing is just Kyung Joon was selected as the prince's companion from when they were kids. As lonely as Nok was, he clinged to him (and for some reason thought highly of him) and treated as a true friend. Such relation could've maybe develop into a real friendship, but it wasn't the case this time. Kyung Joon was loyal as a subject, hoping Nok will be the king, but not as a friend.

To be honest, I never liked him from the beginning. He had shady vibes. The whole talk about marrying his sister was straight up crazy. He doesn't care if his sister dies and all the marriage talk was unnecessary, mf just wanted to make his own worth rise through marriage alliances.
To top all this off, the way he acted around 'lower class' and homosexuals was all I needed to despise him. You just cannot be a good person with such a gigantic stick up your ass. He simply had the 'I need to be the closest to the crown prince because he is going to be the king, which means I am investing in making myself rise' mindset.
Now that his personal moral compass says Lee Nok is not worth being a king, he switches to the side that just aligns with what he wants (more profitable to him in the future + Lee Nok out of the way)
I’mma be honest with y’all, the best friend’s betrayal kinda came from nowhere.
Unless I’m forgetting something he seemed pretty loyal to the crown prince and saw more like a friend than a means to protect his position.
So yeah not a fan of this plot point.