Thank you for the release!
I've seen so many comments, for the novel and webtoon, critisizing the original male lead, Kais, for being very prickly and rude at first (like a stray cat receiving affection for the first time in a long while). Even before this chapter, it was obvious that his wariness came from bad past experiences and concern for his only remaining family member — which, while not commendable, is perfectly understandable at the present juncture. Moreover, this chapter shows what kind of poor treatment Kais was getting: he was a slave (or was at least being treated as one to the point of having a magic enslavement brand to punish him).
Side note: considering his and his brother's looks (not to mention the kind of plot twists these types of stories often have), I wouldn't be surprised if the boys are by blood related to the evil Duke Whatshisname. Not a spoiler, just a guess.