What do I need to do to script the following condition/effect:
If all card zones are disabled by "xxx" effect and your opponent has no cards in their Hand, Deck, Field, Graveyard and Banish Zone.
When this card is Special Summoned: This cards ATK and DEF are equal to the ATK and DEF of the Xyz Materials required to Special Summon this card.
this is the atk function
the first i think is impossible to do as you wrote it, the only thing that can be done is check if the field is all unusable. But a question, how can you opponent have no cards everywhere?