|“||I’ve been looking over you for a thousand years. Of joy and heartbreak. Your fights with Klaus, the nights you cried yourself to sleep calling out my name. Not a day has gone by that I wasn’t right there with you.||”|
Not much is known about this relationship. Rebekah thought her mother was killed by Mikael. But in Season 3 Elena discoveres the truth - Esther was killed by Klaus. Rebekah obviously cares deeply for her mother and refuses to believe that Esther wanted to kill all of her children.
Esther and Rebekah meet in the present for the first time in Bringing Out The Dead, when Elijah revives his siblings, meanwhile, Bonnie and Abby release Esther. Rebekah tries to harm Klaus to avenge her mother, but Esther arrives and stops them. Rebekah is surprised to see Esther alive, and Esther tells the Originals that she wants them to be a family again.
In Dangerous Liaisons, Esther throws a Ball to celebrate the reunion of their family. Rebekah mentions to Kol that Esther made it clear that the guests are not to be harmed. When Esther is speaking to Elijah, she says she is furious at Kol and Rebekah since all she asked was for no violence, and Elijah says he will deal with them. Esther then links Rebekah to the rest of her siblings.
In All My Children, Esther tries to use the power of the full moon and the Bennett bloodline to kill all of her children. When Elijah finds out about this, he holds Elena hostage, warns the rest of his siblings, and leaves Rebekah to watch over Elena and kill her if they are too late. When Elena mentions that Rebekah is still wearing Esther's necklace, she tosses it aside, angry. Later, after Esther is stopped, Rebekah asks Elijah, "Where is Mother?", to which Elijah replies "We have no mother, only Esther."
In Heart of Darkness, Esther tells Rebekah she is dying, but this is just a lie that she used to get Rebekah to let her guard down. She then possessed Rebekah.
In Do Not Go Gentle, Esther successfully fools everyone into believing that she is dead and that she is Rebekah, including Klaus. Esther then returns to her body, after Alaric drives a dagger through Rebekah's heart.