Osiris no Tenkuuryuu, known in Japanese as オシリスの天空竜, is one of the three Egyptian God Cards in Yu-Gi-Oh! Duel Monsters. It is the powerful ace monster associated with Yami Yugi and Atem, often symbolizing divine authority and overwhelming power. In the series, Osiris plays a major role in key duels, especially during Battle City, where its strength and special effects make it a decisive force. The card is also known in English localization as Slifer the Sky Dragon.