Isis is the first child of the head family of the Tomb Keepers. She helped raise Malik and acted as a mother figure to him since their mother died after giving birth to him. Her love for her brother is apparent since she took him to the outside world even though it was expressly forbidden. However it was a grave mistake on her part since it made him resent his station in life even more. She couldn’t stop his alter ego from emerging and killing their father. At his death, she inherited the Millennium Torque that allows her to see into the future.
When Malik left them to kill the Pharaoh, she followed after to attempt to save her brother from the ‘evil spirit’ that possessed him. Along the way, she took a job as curator in Domino Museum where she met Yami Yugi and Anzu on their date. Isis showed them the Pharaoh’s Tablet and told him a little bit about his ancient past. She also lent Kaiba the god card ‘Oberisuku no Kyo Shin Hei’ (Obelisk the Tormentor in the dubs). Isis instructed Kaiba to hold the Battle City Tournament in order to draw the Ghouls out. She then partakes in Battle City to try and free her brother from the evil influence clouding his mind and soul.
Isis’ mother died giving birth to her little brother, Malik. Yami Malik killed their father when she was 14 and she was there to witness his murder. She also see Rishid as family, like an older brother of sorts.
It is quite possible that the Priestess Isis in Atemu’s reign was Isis’ past life. They bare an uncanny resemblence to each other and do act in the same mannerism. Although the Isis in the past life does appear to be somewhat less driven in the same way modern day Isis is.
It has been argued that Isis would be the most likely female canon character that Kaiba might hook up with. Of course, Kisara came into the scene and basically blew that opinion out of the water. The hints are few and far to subtle to be of any real validity. Isis is the only person to address Kaiba as Seto (Mokuba did not call Kaiba “Seto” in the Japanese version). However, one would have to wonder exactly how they would have been able to get along with their differing philosophies. Yet, Kaiba was the one to show her to look beyond the power of the Torque and make her own future.
Isis is a mother goddess of the ancient Egyptian religion. She is the patron of magic and is known for her power. She is still invoked today by Wiccans as an aspect of the Goddess.
Ishtar is the great Prophetess of Mesopotamia. She was known as a great Seer to her people.