I saw some comments stating that it was the Villainess' fault for her treatment being so bad but if you really looked at the story, the only reason she became a villain was because of the way people treated her. She, just like the brothers and the father, distanced herself and eventually obviously an immature girl, hiding away her emotions will need a way to vent that so she became the bad guy everyone saw her as.
I saw some comments stating that it was the Villainess' fault for her treatment being so bad but if you really looked at the story, the only reason she became a villain was because of the way people treated her. She, just like the brothers and the father, distanced herself and eventually obviously an immature girl, hiding away her emotions will need a way to vent that so she became the bad guy everyone saw her as.