Romance, Historical, FL changes her own life, etc.

As the middle child who is neither the heir nor the cherished youngest twins, Karina has lived her whole life hidden away from others. Her only happiness was painting, but it is also eating away her life force. After getting to know she only has 1 year left to live she went to visit her fiancéwithout a plan, asking him to let her stay at his mansion and in return she would agree to cancelling their engagement.

She transmigrated into a novel as Rudbeckia (a supporting character) who died while being used as a tool for political marriage by her father and brother.
Will Rudbeckia find a way to save herself and her new family from her brother and dad's schemes.