Recently a friend (Paulo R. Mendes) asked this question at Sci Fi Ideas : "I want to write a story about a species / culture that is a billion years old and is evil. What would be their reasons, motivations?"
A civilization that is 1 Billion years old may have entire different concepts and morals than us.
For example could the Billiontilas not just be perceived as evil because their actions are not understood?
for example a sentient ant .
How would it describe a boy burning them with a magnifying glass?
The ant would certainly describe the boy as evil. While the society the boy belongs to,thinks of him as an innocent kid playing. Not even a thought wasted on the ant.
How would you describe the motivations of God?
Sending floods and fire to destroy most of creation? Is God evil or good or simply beyond our grasp of realization?
Imagine a civilization that continuously evolves over a billion years. Do you know the entire concept of Homo Sapiens isn’t around that long?
Our perceptions of morals and ethics have certainly evolved for lets say changed from the early cave men. The entire concepts of all world religions including atheism , had to be discovered and place their influence on people.
Why was it perfectly acceptable to burn a witch or a heretic or behead an American in the name of religion and now it is seen as barbaric and unacceptable?
Now expand this concept of moral and ethic evolution across 1 billion years and you will have a result no one of us could understand.
Could you explain to a Viking why his behavior would not be acceptable in let’s say a big office of today?
Or perhaps explain to a stoneage man how a light bulb works, let alone a computer or a nuclear plant?
I think no matter what Paulo will try as an explanation would be flavored by our perception of morals and ethics. Why not simply leave it a mystery
And explain that whatever motivates them to sterilize lesser life forms is evil from the perspective of the destroyed life form but perhaps beneficial and borne out of necessities never even considered .
A bacteria would never condone oral hygiene and call mouthwash an evil invention (kills 99 % of all germs) Yet the benefits of a clean mouth would be lost to that colony of bacteria under your tongue.
The development gap between a 10,000 year society and a 1,000,000,000 year old society would be so profound different .
I doubt we would compete with them for food, space or any other requirements we would consider necessary or motivators for violent action and war.
I doubt you could explain the needs and motivations of a corporation to a three year old, in terms the child could comprehend.
Either make the species or civilization less advanced and thus more understandable or simply state :
“They came and they exterminated bilions, yet all attempts to communicate failed .When contact was finally made, the explanation given was “The Garum seeks the Igohom therefore all nuff must be netoled.”
Made perfectly sense to the Billionite but puzzled the most advanced thinkers until the end when Graum finally snuffed and all humankind was exterminated.