Karina (for a fairytale ending)

This duchess became head of her estate after her husband passes away. She treats everyone except her daughter poorly including her husband's son. Karina's daughter meets with her stepbrother, chained in the basement and become friends. When Karina finds out she attempts to kill her stepson in front of her daughter. When Karina is stopped by her daughter she goes to slap her and the stepson breaks his chains and strangles Karina to death.