If you go back a few chapters, like when they were on the ship, Karas was literally asking everyone what he was supposed to do with his feelings and how he was supposed to act. His whole life has been nothing but cruelty, abuse, and war. He even spent years on the battlefield. The only warmth he ever experienced was during the two months he spent with Abel and he was only 8 years old.
All I’m saying is that neither of them knows anything about intimacy. Abel grew up isolated in the mountains and died at a very young age. He never had any romantic or sexual experience because he spent his entire life training to become a Regas. Karas, on the other hand, grew up being abused, manipulated, and surrounded by people who were constantly trying to kill him.
Again, this isn’t me defending or excusing Karas’ actions. Lack of consent is never okay. I’m just saying that both of them are products of the lives they were forced to live, and that context matters when you're trying to understand their characters.

Y’all are being weird in the comments. This is exactly why it’s better to read the novel because you’ll understand Karas’ character a lot more.
The novel is way darker than the manhwa. There’s a lot more gore, and they even removed all the 18+ scenes in the adaptation. Karas grew up in an abusive household where he was constantly beaten, and almost everyone around him tried to manipulate him since he was a kid. On top of that, he inherited the dragon’s power, so cruelty is basically all he’s ever known. Despite being an adult, Karas is actually really naive. So is Abel. Neither of them knows shit about sex until the very end of the story.
I’m not trying to justify Karas’ actions because anything without consent is a hard no. I’m just reminding y’all that his background has been there since Chapter 1.