Slifer the Sky Dragon, known as "Osiris no Tenkūryū" in Japanese, is one of the Egyptian God Cards in the Yu-Gi-Oh! series. It is a powerful Duel Monster card that plays a crucial role in the series, especially during the Battle City arc. Slifer is known for its unique ability to increase its attack power based on the number of cards in the player's hand. This dragon is a symbol of immense strength and divine power, often seen as a pivotal weapon in the protagonist's deck. Slifer's presence is often associated with critical turning points in the series, highlighting its importance in duels.