Reaper Energy is actually a type of Magic Energy of the Spirit which acts as a force of nature to enforce the balance between the transference of energy from the Spirit to reality and back again. Reaper Energy, similar to Mental Energy, can also twist the minds all living things, bringing them under the control of the warping powers of magic. This forces them to act in the interest of restoring balance, for good or for evil. Reaper Energy is also known to break any concentrations of magic and disperse it to the Spirit which can have drastic consequences for those infused by large concentrations of Magic, ranging from being severely weakened to disappearing altogether. Those possessed by large amounts of Reaper Energy may start to lose themselves in an insanity that consumes them.
Reaper Energy can also possess the carbon in the earth as well as plant life and animals leading to extremes in death and decay or robust overgrowth. As a form of energy from the Spirit, Reaper Energy is also Magic: Magic Lore. Thus, Reaper Energy is stored in living or once living tissue and builds up, as all Magic. The distinction however between Reaper Energy and other forms of Magic Energy is that Reaper energy naturally enhances other Magic Energy, especially as it builds up. Additionally there is nothing stopping Reaper Energy from building up in mass quantities so long as an imbalance exists.
Reaper Energy and the People of Indagar
The people of Indagar do not know of Reaper Energy, and they do not have a name for it. Those whose bodies are attuned to detecting Magic can detect it, but to them, it appears as a slightly "off" version of the normal magical energy they can already detect. They may feel it to be weaker or perhaps somewhat tainted versions of other magical energy. This is because Reaper Energy shows similarities at a very granular scale to all forms of other magical energy.
Since Reaper Energy is not known to exist by the people of Indagar, they do not understand it nor refer to it. It is not written about or found in scholarly manuals. Even those who have become fully possessed by it simply do not understand what has caused their changes and instead appear to outsiders as merely a conglomeration of all forms of Magic energy.
Reaper Energy, or the Reaper, is a natural force that primarily exists in the Spirit. Like all forms of magic energy therein, Reaper Energy can leak into our physical reality. However, typically the laws of the Universe which govern the flow of energy from the Spirit maintain Reaper Energy within the Spirit without it being released in large quantities. When the natural flow of energy from the Spirit to reality is interrupted, however, Reaper Energy begins to flow in greater earnest from the Spirit, invading reality to a higher degree.
Reaper Energy is unstable in reality and is constantly seeking to return to the Spirit at a much higher rate than other forms of Magic energy so long as balance exists. The properties which govern Reaper Energy tend to twist living matter in less subtle ways than other magic, with the result either being a body being broken apart and fading to the wind, or warping a mind towards a purpose of hostility and carnage. Thus, if Reaper Energy fully possess a plant, it may shrivel the plant to death or mutate it to become poisonous to other plants around it.
However, the Reaper has also been known to have beneficial effects such as healing and strengthening a being. This contradictory nature is because Reaper Energy serves a distinct purpose in the Universe to resolve issues of imbalance in the natural flow of magic energy between reality and the Spirit. Thus, when too much Magic is being held in reality, such as bottling it up in Spirit Refinement, Reaper Energy released into reality will seek to destroy life, freeing magic energy trapped in organic material. If too much magic is returning the Spirit from reality, Reaper Energy is released to bolster life and create extreme growth.
Benefits of Reaper Energy on the World
Without Reaper Energy, the magic from the Spirit would eventually fall out of balance. This would mean that creatures and plants infused with too much magic would become practically unstable as they feed on all other living things and become too powerful for others to stop them. The Reaper Energy weakens these beings as they become too powerful and allow other life to sustain itself. Additionally, too much magic would begin to mutate all life and the Reaper controls this effect.
It is important to note that the effect the Reaper has on magic infused creatures and plants is generally, very destructive, either in death or growth. Therefore as more people start to infuse themselves with magical energies and as more magic spills into the world, the more Reaper magic will appear to be a catastrophe as seen in the Cataclysm.
Personification of the Reaper
The Reaper is not sentient nor living at all. It is merely a product of natural law. However, since that natural law seems to adopt purpose, especially in its tendency towards restoring the balance of the flow of Magic, the Reaper can be personified. Almost as if a God of Balance, the Reaper invades reality with the express purpose of restoring the natural order of things.