What is a god card?

Answer 1

A God Card refers to one of the three cards that were the main focus of the second arc of the original Yu-Gi-Oh! series. Konami released all three God Cards in tournament-illegal prints, and has since then released Effect Monster versions of Obelisk the Tormentor and The Winged Dragon of Ra. The effects of these cards are as follows:

Obelisk the Tormentor (Effect Monster)

DIVINE/Divine-Beast/Lv10/Effect

ATK: 4000 DEF: 4000

You must Tribute 3 monsters you control to Normal Summon this card (You cannot Set this card). The Normal Summon of this card cannot be negated. When this card is Normal Summoned, a Spell, Trap, or Effect Monster card cannot be activated. This card cannot be targeted by the effects of a Spell, Trap, or Effect Monster. If this card is Special Summoned, it is sent to the Graveyard at the End Phase. You can Tribute 2 monsters you control to destroy all monsters on your opponent's side of the field. This card cannot declare an attack during the turn this effect is activated.

The Winged Dragon of Ra (Effect Monster)

DIVINE/Divine-Beast/Lv10/Effect

ATK: ? DEF: ?

This card cannot be Special Summoned. You must Tribute 3 monsters to Normal Summon this card (You cannot Set this card). The Normal Summon of this card cannot be negated. When this card is Normal Summoned, the effect of Spells, Traps, and Effect Monsters other than this card cannot be activated. If this card is Normal Summoned, you can pay Life Points so that you only have 100 left to have this card gain ATK and DEF equal to the amount of Life Points paid. Also, you can pay 1000 Life Points to select and destroy 1 monster on the field.

Slifer the Sky Dragon (From Yu-Gi-Oh! World Championship 2010: Reverse of Arcadia)

DIVINE/Divine-Beast/Lv10/Effect

ATK: ? DEF: ?

You must Tribute 3 Monsters you control to Normal Summon this card (You cannot Set this card). The Normal Summon of this card cannot be negated. When this card is Normal Summoned, a Spell, Trap, or Effect Monster Card cannot be activated. This card cannot be targeted by the effects of a Spell, Trap, or Effect Monster. If this card is Special Summoned, it is sent to the Graveyard during the End Phase. The ATK and DEF of this card becomes the number of cards in your Hand x 1000. When your opponent Normal Summons or Flip Summons a monster(s) with 2000 DEF or less, destroy the Summoned monster(s).