Often called "Majoko" throughout the series ( a pun nickname involving the word "Majo", 'witch', and her own name), Mayoko Okino is known in the series as the "Witch of the West". She was first shown flying with her broom over a site where Ango Shima was fighting against a Mononoke. She was later formally introduced when presented to her new class (Kujo's class), as a transfer student coming from Kyoto, along with Shima. It is implied that she knew Ango beforehand, as she states that they might have already fought once.

As a witch, she also has a familiar: a nekomata named Senryou (who is, supposedly, her boyfriend), portrayed as small, black cat whose tail's divided. His eyes are also colored differently, as the left one is indigo and the right one, golden. He has pleaded her loyalty she saved his life.