cercei's eighteen years of existence were marred by excruciating pain and suffering solely because of her uncanny resemblance to Vienna , the Alpha's daughter . Cercei found it unbearably cruel that she possessed the same beauty as Vienna , which made Vienna feel insecure , leading her to subject cercei to relentless torment. Despite the numerous hardship , cercei received love and care from her parents, and she remained humble , although their Alpha never respected them and treated them as mere servants ,her family found happiness . However , everything changed dramatically on her eighteenth birthday when their Alpha ruthlessly killed her father without a valid reason and mercilessly crushed his heart under his feet after digging it out. Enraged and seeking revenge , cercei felt powerless until she encountered the King Alpha of the North, whom she slept with . This chance encounter changed her life abruptly , cracking all the hidden secrets and lies her mother had carefully concealed for eighteen years . The revelation shattered cercei 's belief in her perfect family and parents, leaving her questioning everything she had ever known.