*Something that Poisoned the enemy and protected a permanent would not count since the poison would not fit in Earth and the protection would not fit in Death.
...what?
Than consider it like this: The effects fit in any element. So I can put them in technically any hybrid. However the card and its design limits it to light and dark.
The Earth/Death comparison I made was to give a clear example of something that did not fit completely into each element and thus could not have a hybrid cost.
If it is true that the effect fits in any element, then it should be possible to pay it with any quanta.
If the effect fits either of 2 elements, then it can be possible to play it with either quanta. Hybrid
If the effect does not fit an element, then it should not be possible to play it with that quanta.
Hybrid costs (A/B) allow a player to play the effect with just quanta A, just quanta B or a mixture of quanta A and B. Thus if an effect does not fit in element A, it should not have a hybrid cost that involves A.
Back in the day Light and Death each had a shield that cost 3
|2
and give DR 1. There is no part of a DR 1 shield that did not fit in Light and there is no part of a DR 1 shield that did not fit in Death. So it would have been reasonable to give the DR 1 shield as Light/Death hybrid cost. (However Zanz also realized that it fit in every other element so he changed the cost to 1
|5
and made it a DR 1|DR 2 shield)