humans destroying their homes and killing them and their resources. (food, mating grounds, etc)
Humans
You'd have to be more specific about when, but the most likely answer is the Persian Empire, led by Darius III.
threatening
It is not life threatening if it is minor.
He had a life-threatening illness.
YES!!!!!! it is very life threatening!
No, nothing is threatening the Falls.
Her threatening demeanor made me decide to change the subject.
The dark clouds in the sky looked threatening as they loomed over the town.
Heat stroke is immediately life threatening.
Yes, alcoholism can be a life-threatening disease.
to be true a non threatening emergency is when you have a problem but it isn't a life or death problem