Who is Meredith 'Merry' Zachariah from The Murderer's Daughters and what is their importance?

Meredith 'Merry' Zachariah is Joey and Celeste Zachariah's youngest daughter. When her father murdered her mother, he also stabbed Merry, who survived the attack. When she was a little girl, she begged to see her father relentlessly, as she grew older, however, and began to understand exactly what happened, she would rather have avoided the visits. She continues to see him because she believes it is her duty.