"A Poltergeist that's close to maturity…" Re'Kha muttered, shuddering at the thought, "Considering the way it managed to kill two Balou with one hit, this might very well be the case."
After a Poltergeist takes root in a place, it seeps its control into all the man-made objects present in the land. A Poltergeist that takes root in a part of nature untouched by people would be perfectly harmless.
It was because it couldn't try to take control of nature. It was the sheer difference in their leagues, as the opponent it was trying to snatch a piece of consisted of the entire world. And, judging based on historical accounts where the cultivation technique of the Royal Clan was given to them by the world and such, it was evident that the world had a will of its own.