Good and Evil

"...the world isn't split into good people and Death Eaters. We've all got both light and dark inside us. What matters is the part we choose to act on. That's who we really are." -Sirius Black

There is good in everyone. However, we all make mistakes, and we all hurt each other. None of us are perfect, and none of us ever will be. Darth Vader had good in him, Luke had anger and hate in his heart. Harry Potter wasn't flawless, he broke many rules. However, there exist, at least in fantasy, those who have no goodness in them. Examples would be Lord Voldemort and Emperor Palpatine. It isn't likely that these kind of people exist in real life. If they do, it is most likely due to illness and not to a sheer lack of compassion.

"It is important to fight, and fight again, and keep fighting, for only then can evil be kept at bay, though never quite eradicated." - Albus Dumbledore

This quote is highly true. Evil in our world means basically those who would neglect or hurt others in order to gain things for themselves. We try in our everyday lives to prevents these kind of people from achieving their means. It also speaks of how evil can't be silenced for good, it will always appear in genetic flaws, or human mistake.