I know this part isn't M rated but we will get there...
After Eli's death Ziva was devastated. She was the sole survivor of her family. Israel and Mossad had taken her family away from her.
Her mother. She didn't even want to think about her. After her father left with Orli, she was devastated and went into a deep depression. After two years in hell, taking care of Tali and Ari as the mother figure in the house, Rivka had taken her life, leaving a simple note to her kids; אני אוהב אותך.
Then there was Tali. She was officially killed in a suicide bombing but she knew it had been an attack on her to make her father sign an accord with hamas. It made her sick that her innocent and compasionate baby sister was killed for peace.
She was the one to blame for Ari's death. She had regrets, she took the life of the only other person from her homeland she could truly confide in. Shmeil was a great friend but he had this way to turn things into deep philosophical questions. The only thing that could comfort her was that by killing Ari, she had found a new family, a father in Gibbs, a sister in Abby, a brother in McGee, a grand-father in Ducky, a little cousin in Palmer and the love or her life in Tony.
Finally, there was Eli. Her father, the one who left her to die in the somalian desert. Why did she even care for his death ? He was her last living relative. He was the only way to remind her of her childhood happiness. And his job, his country, his religion, took that away from her. She had been a Mossad officier, loyal to her country and her heritage but she was very bitter.
She had killed her childhood friend, her father's protégé, Ilan Bodnar. They had shared so many things together. Tony had kill Michael. Amir was killed protecting Eli. She wanted to kill Malachi as much as she hated her father for leaving her to die in Salim's camp. Apart from a few aunts and uncles she hadn't spoken to in years, she had nobody left in Israel.