Chess

Our life in this world is like a chess or chessboard. Some are white and then others are “black” and then they all keep fighting with each other.
But if some other color accidentally “gets lost” in there, for example gray or yellow then both of these “extremes” are lost.

I don't know why this is happening?

Queen's Gambit Scene: The Final Chess Game - Last Episode

What is there reason that life always has a need for more healers here to balance the “evil” and “greed” that is rampant everywhere here, or if there were no negative people (or feelings), there would be no need to heal people and everyone would be “until old age” alive and well.