Editing Slifer the Sky Dragon (section)

=== Project R.A. ===
During Yako Tenma’s first Duel against Yami Yugi, Yugi summoned "Slifer the Sky Dragon" by sacrificing his "Magna Warriors." Despite the formidable presence of the Egyptian God, Yako remained unfazed and countered by summoning his own "God card," "The Wicked Avatar." Initially appearing as a black orb, "[[The Wicked Avatar]]" transformed into a mirror image of "Slifer."

Yugi attempted to use "Slifer's" second mouth effect to destroy "Avatar," but the attack failed due to "The Wicked Avatar's" placement on the Divine Hierarchy, which granted it superiority over "Slifer." "Avatar" then obliterated "Slifer" in a single attack, later revealed to be a result of its unique ability to take on the highest ATK on the field plus one, ensuring its dominance.

While often associated with the other Egyptian Gods, "Slifer" had only one additional appearance during Project R.A. It was briefly summoned to effortlessly defeat Cedar Mill as Yamo Yugi and Gekko Tenma ascended to the top of the Kaiba Corporation building.