* De-Fusion's Effect: De-Fusion is a Spell Card that allows you to banish one Fusion Monster on the field and one Fusion Material monster from your hand or field to Special Summon the Fusion Material monster.
* Card Effects vs. Cards: De-Fusion targets cards (specifically, Fusion Monsters and Fusion Material monsters), not effects. It doesn't interact with the abilities or actions that cards provide.
* Focus on Material: De-Fusion's function is about manipulating the materials used to create Fusion Monsters, not altering their effects in any way.
Think of it like this: De-Fusion is a tool for rearranging the building blocks of Fusion Summons, not a tool for changing the properties of those blocks themselves.