Golden Demon allows Kōyō to summon a female sword-wielding phantom, which is quite similar to Kyōka Izumi's ability. However, unlike Kyōka who needed to initially activate and control her ability through an intermediary phone, Kōyō can manipulate her ability freely, and she control its activation and dissipation at will. Like Demon Snow, Golden Demon has a high offensive power and force capable of inflicting wounds through its katana with high speed and accuracy.
The ability is a reference to the real-life Kōyō Ozaki's novel The Usurer (金色夜叉 Konjiki Yasha?, literally "The Golden Demon"), which was serialized in 1897. Widely considered as his masterpiece, the novel depicts the social cost of modernization when money wins over both human affection and social responsibility.