Card Rulings:De-Fusion

• If the Fusion Monster returned to the Fusion Deck by "De-Fusion's" effect was not Fusion Summoned (i.e. "Cyber-Stein" or "Magical Scientist"), the card's second effect will not work.

• Special Summoning the Fusion Material Monsters is an option. So you may use "De-Fusion" to return a Fusion Monster to its owner's Fusion Deck even if you have only 1 or none of the appropriate Fusion Material Monsters in your Graveyard.

• If you have only 1 of the Fusion Material Monsters in your Graveyard you cannot Special Summon it.

• You may use "De-Fusion" to Special Summon "Goddess with the Third Eye" or "King of the Swamp" if it was used as a Fusion Material Monster for the Fusion Monster selected with "De-Fusion".

• After you attack with a Fusion Monster, you may activate "De-Fusion" in the End Step of the Battle Phase to Special Summon the appropriate Fusion Material Monsters and attack with them in the same Battle Phase.

• If you activate "De-Fusion" and select a Fusion Monster that was Special Summoned by "Magical Scientist" or "Metamorphosis" you can return the Fusion Monster to the owner's Fusion Deck, but cannot Special Summon any Fusion Material Monsters since none were used.

Mentions in Other Rulings

• Chimeratech Overdragon: You can activate "De-Fusion" and target "Chimeratech Overdragon", but you can only Special Summon the Fusion Material Monsters if you have enough vacant Monster Card Zones for ALL of the Fusion Material Monsters you used.

• Diffusion Wave-Motion: If you Special Summon a monster during the Battle Phase after having activated "Diffusion Wave-Motion" (such as with "De-Fusion"...), that monster cannot attack because "Diffusion Wave-Motion"'s effect prevents all monsters other than the selected Level 7 Spellcaster-Type monster from attacking.

• King Dragun: Your opponent cannot target a Dragon-Type Fusion Monster with "De-Fusion" while "King Dragun" or "Lord of D." is on the field because "De-Fusion" targets.

• Proto-Cyber Dragon: If "Proto-Cyber Dragon" is used in the Fusion Summon of "Cyber Twin Dragon", and "De-Fusion" is used on that "Cyber Twin Dragon", you cannot Special Summon the "Proto-Cyber Dragon" from the Graveyard because its name is not 1 of the listed Fusion-Material Monsters. (It's no longer treated as "Cyber Dragon" while in the Graveyard.)