Slifer the Sky Dragon

Slifer the Sky Dragonis a egyptian god dragon from the Yu-Gi-Oh! franchise and video games. It was owned by Marik, but then Yugi took pessision of it.

Ancient Egypt
Slifer is one of the three Egyptian Gods, along with Obelisk the Tormentor and The Winged Dragon of Ra. These monsters were only capable of being summoned by the Pharaoh.

When Atem spotted Thief Bakura fleeing from the palace after he had attacked Aknadin, he chased after him on horseback and Summoned Slifer to fight Bakura's Diabound. Atem allowed Slifer to be struck in order to protect innocent civilians from Diabound's attacks and then got Slifer to force the battle into the sky. However Diabound was able to disappear into the darkness and attack Slifer from behind. Atem pretended to surrender his Millennium Pendant in order to distract Thief Bakura while he had Slifer sneak up on him. However Bakura got Diabound to make a similar sneak attack on the Pharaoh.After the priests arrived, Atem sacrificed Slifer, so that Seto's Duos could attack Diabound, but Duos wound up hitting a decoy ka instead.By defeating Slifer, Diabound gained its power, including its "Thunder Force" attack.

Battle City
3000 years later, Maximillion Pegasus created cards depicting the three Egyptian Gods, for his game Duel Monsters. However the souls of the Gods came to dwell in the cards, making them powerful weapons. On realizing this, Pegasus regarded their creation as one of his greatest mistakes. He tried to destroy the God Cards, but could not bring himself to do it, so he had the Egyptian supreme council of antiquities bury the cards in different locations in the Valley of the Kings. The Ghouls managed to steal the "Slifer the Sky Dragon" and "The Winged Dragon of Ra" cards. However the Egyptian supreme council of antiquities was able to prevent them finding the "Obelisk the Tormentor" card. Ishizu Ishtar, from the council, later gave it to Seto Kaiba, so that he would host the Battle City tournament to retrieve the other two.

The leader of the Ghouls, Marik Ishtar entered the Battle City tournament with the "Slifer" and "Ra" God cards. Using Strings as his puppet, he Dueled Yami Yugi in the preliminaries and used "Slifer the Sky Dragon" in the Duel. However Yami managed to win the Duel and won the "Slifer" card through the tournament rules.

Yami Yugi used "Slifer the Sky Dragon" in his semi final Duel against Yami Bakura. Summoning it and attacking Yami Bakura became Yami Yugi's only way of winning the Duel. Marik exploited this, by having Yami Bakura remove his control over Ryo Bakura's body. Ryo, who was injured and significantly weaker than Yami Bakura would not be able to withstand an attack from Slifer, making Yami Yugi reluctant to attack. However, Yami Bakura took back control of Ryo's body and urged him to attack, assuring him Ryo would be okay.

During Yami Yugi and Kaiba's semi final Duel, they got "Slifer the Sky Dragon" and "Obelisk the Tormentor" to battle, which caused Yami and Kaiba to see a vision of an ancient city. Here Slifer and Obelisk were turned to stone, while Priest Seto and Pharaoh Atem battled.

Yami used Slifer in his final Duel against Yami Marik.

Doma
In order to regain his memories, Yami Yugi presented the three Egyptian Gods to the stone tablet in the museum. However, the God cards began to crackle with black energy as Dartz drained their power. Yami was then interrupted as Duel Monster spirits began appearing throughout the city. Later that day, Dartz's men broke into Kame Game and stole the God Cards. Dartz placed the cards in the mouths of three stone serpents in order to use their power to summon The Great Leviathan.

After defeating Dartz in a Duel, Yami retrieved the Egyptian God cards, though their strength had already been drained. After Yami Yugi's soul had been absorbed into The Great Leviathan, the other souls Dartz had captured were able to lend him their strength. With it, Yami called out, "In the name of the Pharaoh, awaken!" and summoned the three Egyptian Gods. By summoning them, Yami was also able to free himself, Joey Wheeler and Seto Kaiba from the Leviathan. Obelisk, Slifer and Ra engaged in battle with The Great Leviathan. The three combined their attacks and seemed to defeat it at first. However the Leviathan reappeared in a different form, which Yami managed to defeat.

Pyramid of Light
Kaiba Dueled and defeated Pegasus to obtain a card capable of defeating the Egyptian God cards. Anubis added an extra card, "Pyramid of Light" to Kaiba's prize. Kaiba went on to face Yami Yugi in a Duel and used "Obligatory Summon" to force him to Summon the Egyptian God cards and then activated "Pyramid of Light", removing the Gods from play.

Memory World
When Yami Yugi entered the Memory World, he relived some of his life as Pharaoh Atem, and fought the battle against Thief Bakura, in which he summoned Slifer, again.

The Pharaoh used the three Egyptian Gods to battle Zorc Necrophades. However Zorc managed to overpower them and turn them into stone. Upon relearning his name, Atem was able to summon the three Gods again, this time from the cards in Yugi's Deck. He then combined them into The Creator God of Light, Horakhty, who defeated Zorc.

Yugi and Atem constructed separate Decks for the Ceremonial Battle, which Atem needed to lose in order to pass on to the afterlife. Despite needing to lose, Atem gave the Duel his all. He included the three Egyptian God cards in his Deck and managed to summon the three of them at once in the Duel. However Yugi was able to destroy them and win.