Without reading the novel and from the start of the story, you can feel all the things you need from the brother:beware of him, do not stay close, always say "yes" because you do not know what might happen if you do not agree with him... I think I have read lots of webtoons lately but no character has given me the creeps as this one. Every time I read a new chapter I am telling myself this is just temporary, because I am hoping he will be find out soon and get killed or just get tortured the way the main character was.
Thanks for reading me.
Go seduce.
Then go to the store and make urself a dress full of jewelry.
Show it to the world.
Nobody will complain and your nightmares will disappear :)