Omega
There is a force of primal Light in the universe. Just as Chaos represents utter Darkness, the force most commonly called “Omega” represents absolute Light. While Chaos and Omega are often anthropomorphized by people seeking to properly understand them, they do not possess wills or minds of their own. There are no great titans of Light and Darkness clashing in the space between worlds; there is merely Light and Darkness, and the result of the inherent opposition of the two metaphysical forces as it manifests on the rest of reality. Some say that the presence of Omega and Chaos sparked the Keyblade War. Others claim that the Keyblade War in fact created Omega and Chaos as they are understood now. Despite the numerous myths and legends with these labels attached scattered across the worlds, it is unlikely the truth will ever be known.
Points of intense Light, of Omega, were scattered throughout the worlds long ago. Some of them came to them when the world was born; others, in particularly ancient worlds, arrived during times of true antiquity. These “shards” join with Hearts in the world the same way seeds of Chaos do, and when a bearer of one perishes, the shard finds its way to another new Heart born, continuing the cycle. They may not immediately manifest within an individual, but when they do, their own Heart is granted a measure of Omega's immense Light, and a part of its desire to do good and defeat Darkness.
When a shard of Omega inhabits a creature without sapience, such as any of the innumerable monsters throughout the worlds, it gradually transforms it into a vessel to combat Darkness. They find themselves drawn to do just that, as guardians and sentinels that do battle with the things that contain darkness throughout the worlds. Their instincts are swayed to this purpose, and as a result, they find themselves unable to attack or even threaten a Princess of Heart or other vessel of powerful Light, once confronted with them.
When a shard of Omega inhabits a sapient creature, such as a human or any number of other intelligent peoples' present on these worlds, they undergo a similar change. Unlike animals and monsters, people possess their own free will, and aren't wholly directed by the shard of power they've been given; instead, they're influenced, and their decisions are colored by the desire to fight Darkness. While they are predominantly heroic in nature, possessing a shard of Omega like this does not mean they can't be villainous, though it is just as unlikely as a seed of Chaos being a true blue hero.
Individuals possessing a shard of Omega gain an instinctual desire to combat Darkness in all its forms. This instinct functions as something of a sixth sense, allowing them to detect particularly potent sources of Darkness in the vicinity for the purpose of doing battle with them. Experienced bearers of one of Omega’s shards learn to hone this sense into something they can focus on over time; otherwise, they must simply rely on gut feeling and the prickling hostility towards certain individuals they might experience. The drive to fight the Darkness is constant, and if a particularly large and powerful source of it presents itself, the Omega instinct to destroy it can be almost overwhelming, making a confrontation inevitable.
On the flip side, Omega recognizes when a being possessing powerful Light is nearby, and an instinctual desire to protect or preserve them rears its head in this case instead. While an individual with a shard of Omega might not realize that someone is a Princess of Heart, for instance, they’ll still find themselves having difficulty confronting them in a threatening manner -- though, of course, a human’s free will can override instinct. Should they truly wish to do something so heinous, it is inevitable that their guilt at the act will make it unlikely they’ll ever do it again.
A particularly powerful being possessing a shard of Omega roams the space between worlds. Once broken apart by a tremendous force of Chaos, the being is now scattered into pieces of its body, each roaming the universe and mindlessly seeking both Darkness to destroy and the other parts of itself. While it is sometimes called Omega, it is most certainly not a physical manifestation of the metaphysical force. Still, it is on a scale that means that facing parts of it is only really possible for something like the Unlimited, Keyblade Masters, or for especially powerful seeds of Chaos -- and even then, only to fight it off, not to destroy it.
On some worlds, manifestations of Omega have taken the form of powerful magical fonts in the form of the Crystals. Most commonly found in fours and corresponding to the four classical elements, Crystals are nonetheless manifestations of Light and Good. Crystals are elementally-aligned primarily due to their interaction with the forces of the planet itself, shaped in part by the world just as shards borne by humankind manifest in differing ways. Certain warriors who fight for the cause of Light have said that the Crystals speak to them or grant them extraordinary abilities, and while they may feel a strong urge to combat their world’s Darkness from the Crystals or be bolstered by their Light, they are no more intelligent than any other rock on the planet. A being called Clear, sometimes referred to as “Omega’s heart,” may somehow be connected to this... but it’s unlikely anyone will figure out how anytime soon.
