charmed
The  concept embodies the concept of Good and Evil

The Yin and Yang concept embodies the concept of Good and Evil

In the Charmed universe, morality is not a matter of perception, but an objective absolute. "Good" and "Evil", rather than being a label for a particular pattern of behavior, are set affiliations, as if they are the political parties of the supernatural world. Each has a hierarchy, agents, and an agenda. As with political groups, characters are fully aware of their affiliation and have the ability to switch between the two with relative ease.

Nature

Leo: "Death is a part of life."
Alpha: "Natural death, yes. But not the death caused by the pointless, endless battles between Good and Evil."
Leo: "They're not pointless. They're necessary. And when good wins..."
Alpha: "Wins? Duality is self-perpetuating. It feeds only on itself. That's why the battle has been raging since the dawn of time. There is no winner."
— Leo and the Avatars discussing about the nature of Good and Evil.[src]

Oddly, good and evil behavior seem to be a consequence of a character's affiliation, rather than the reverse. That is, a character does not belong to Evil because they are selfish and cruel; their selfishness and cruelty are the result of being affiliated with Evil. An otherwise good character who is forcibly converted to Evil will begin to manifest selfishness and cruelty. An otherwise-evil character who is forcibly converted to Good will find their selfishness and cruelty vanish of their own accord.

However, because the world is not just black and white, a good being can commit an act of great evil without being turned to the side of evil. Such an example was when Leo and future Chris ruthlessly murdered Valkyries to help the Charmed Ones. While the reasoning behind this is not clear, it could be because they felt guilt for their actions, and their actions were motivated by a desire to serve the Greater Good. Another example is Christy Jenkins believed she was serving the Greater Good by killing the Charmed Ones, and Neena believed she did what she did for the Greater Good. Evil creatures, however, generally enjoy killing and generally only have petty reasons for doing so.

Organization

The forces of Good, led by the Council of Elders, consist of good witches, Whitelighters, angels, and benevolent supernatural beings such as leprechauns and nymphs. Good beings provide healing, foster positive emotions, and attempt to protect innocents and vanquish evil.

The forces of Evil, under the leadership of the Source of All Evil and the Triad, consist of demons, warlocks, evil witches, Darklighters and assorted maligned supernatural beings such as Banshees, vampires and harpies. Evil beings are chiefly concerned with acquiring power, performing acts of cruelty, destroying powerful Good beings, attempting to harm innocents, and increasing their influence in the mortal world.

Balance

An intended part of the Grand Design is that there must be a balance between Good and Evil, or the world will literally stop spinning. Any switch between the two sides must happen naturally, over time, and upon the creature's free will. Any other type of conversion is dangerous. As shown in "It's a Bad, Bad, Bad, Bad World", a world with too much good is just as dangerous as a world with too much evil.

According to Gideon, every world of good needed to be counterbalanced in the existence of a parallel world where evil reigned supreme. His plot to destroy Wyatt proved the dangers of a world that was entirely dedicated to punishing the guilty. In this world, every small break of the rules was a capital offense, with the penalty often nothing short of the removal of limbs, and, more often than not, death.

Also, since the cosmic balance needed to be offset, the existence of the Charmed Ones as the greatest known force of good was counterbalanced by the existence of the Rowe Coven as their destined evil antithesis. However, later, two of the brothers were killed while the youngest was stripped of his powers by being ordained to a catholic priest, which did not seem to result in the reconstitution or ascension of a new trio to offset the balance.

Also, when Paige cast a spell for stress relief, she inadvertently created two identical copies of a perfect mate from her emotions, Vincent Right of the positive and Vincent Wrong of the negative.

Neutrality

Some supernatural beings are Neutral, like the Angel of Death. They are not aligned with either Good or Evil, and do not participate in the eternal struggle between them. Instead, they perform other functions in maintaining the Grand Design, or are free to pursue their own agendas. It should be noted that Neutrality is not an affiliation; it only indicates a lack of affiliation with Good or Evil. Two Neutral beings, such as an Avatar and an Angel of Destiny, will not necessarily be friendly to one another.

Other Neutral beings include the Avatars, who do not align themselves with good or evil, but act independently in their attempt to create Utopia. They seek to change the Grand Design rather than maintain it as is.

It is said that there will be a final battle between good and evil, for which all the Valkyries train for, to fight for the side of Good. It is never quite mentioned in Charmed as to when this will happen.

Change of Morality

Turning Evil

Phoebe, possessed by the Shadow, trying to attack Piper

Phoebe, possessed by the Shadow, trying to attack Piper

Throughout the series Charmed, there are examples of witches, humans, Elders and other beings that strayed from the Greater Good and let evil to spread within their persona, either by their own choice or by magical means.

This phenomenon is known as the Lucifer Effect in the real world where people stray from being individually moral to committing acts of evil, and become corrupt and cruel towards others as a result of pressure under specific circumstances, such as fear for one's life, peer pressure or simply being destructive because of collected anger and hate.[1]

Turning Good

There are cases where a magically evil being, such as a warlock or a demon, chooses to resist their dark nature and choose the path of good as long as they are given a solid reason, such as falling in love with a good being or developing a conscience.

By Choice

Witches
Warlocks
Demons
Angels
Other magical beings
Mortals

Magical Corruptions

Transformations
Other means

Notes and Trivia

References