The crown prince is the ml, the first time they met he was a bit violent but you have to remember he also literally had a assassination attempt like 5 minutes before that, once they meet again and after the incident, there's really no question who is gonna win in that race.
All i will say about ikles is she will regret saving him very much later, not all love is a good thing.
For a bit more spoilers, specifically about the "heroine", she's neither a white lotus or a villainess, she's literally a eldritch horror probably as close as possible to this world's satan, possessing the deceased blood sister of duke's family's skin, not only that, this isn't the first time penelope has been reincarnated, the mc (which yes, is the korean girl), is the original penelope from the novel, she didn't "transmigrate", she returned to her original body, but she'd been murdered so many times that it fragmented her soul and she forgot everything, the korean penelope was a twist of fate that allowed her to gain some knowledge outside of the world and realize beforehand what was going to happen to her, and plan accordingly, penelope is the only decendant of the people who sealed away whatever the heroine's race was, which as i said are probably closer to demons, each time penelope died, the world became a hell on earth before being destroyed and the cycle repeating.
Oh and one more thing about the "heroine", she not only has charm powers (which aren't like what you see in manga, it's essentially a form of brainwashing on a wide scale, to the point of being able to control armies, and only those with a strong conviction to fight it can actually resist it), this charm power is also used to "curse" penelope and make people mistreat her, even her korean family's treatment of her was due to this curse, it's literally bound to her soul, her breaking it in this timeline reveals a few things to make the korean family and everyone else more sympathetic, but yeah, basically the whole world really does have it out for her, because the big bad has made EVERYONE hate her as a default, and breaking the suggestion is more or less the actual plot of the story.