Rebekah's Host

Rebekah's Host is a character introduced in The Map of Moments. She is a young witch that was at some point in her life trapped in the Asylum where mentally-ill witches were sent.

She was eventually prepared by Kol Mikaelson as a vessel for the spirit of his younger sister, the original vampire Rebekah. Soon after, her body was inhabited by Rebekah's spirit.

History
She is a young witch who was at some point during her life sent to the Asylum, possibly because of angering one of the vampires, or posing a threat to Klaus, seeing as the Asylum was commonly used as a prison for witches who went against Klaus, under the pretense that all of them were mentally-ill.

Later on, the former original vampire Kol, now in the possession of a witch named Kaleb prepared the girl's body as a vessel for his sister Rebekah's spirit to jump into once his mother performs the body-jumping spell on Rebekah. Kol however lied to his siblings about preparing the body of a girl named Angelica, when infact, he prepared the body of a witch imprisoned in the Asylum. After Davina managed to protect Camile's body from Esther's possession spell, Rebekah's spirit was redirected into the body of the young witch. As she woke up in the Asylum, in her new witch body, she started hearing voices & laughter and suddenly runned down the stairs, trying to get out of the mansion while screaming that she is Rebekah Mikaelson & realising that Kol has tricked her.

Trivia

 * It is possible that the witch was brought by Kol into the Asylum only after her body was prepared as a vessel for Rebekah, due to the fact that if Kol entered the Asylum, he would have been trapped inside.
 * Her name & backstory so far remain unknown.
 * It is unknown what exactly got her imprisoned in the Asylum, however it is known that the Asylum is a place where insane witches go.