Коґуре Сая

Saya is an enigmatic woman who is, at times, hidden from view of most people. She is the Tachibanas' next door neighbor, and is in the fashion industry. But this is only an illusion—she covertly pushes circumstances in Ichika's life to bring her to use the power of the Djinns. She can move anywhere at will, turn her scarf into a deadly scythe and other objects and keeps an eye on Ichika throughout the series. She strictly enforces rules concerning the activation of the stones: the current bearer must remain completely in the dark as to their true nature and purpose and no one may interfere with the bearer's decision whether to use the power. (from wikipedia)