i think you should use both. i think you should use option one first and leave it as a mystery as to who is behind the Zero "plague". Later on reveal that this dying man concieved this destruction in order to bring people "to their knees before God." The reason? his death and he want to take others with him because he feels it's unfair he has to die? or maybe he's trying to make up for past sins by taking out a sinful nation? i don't know but i think both work...but option one should be the beginning of the story.
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