Soul

A Soul is an aware emanation / manifestation of the Song of Creation, that resides within a living — or at least once living — creature. It is debated whether all creatures which are aware and/or sentient have souls, though the orthodox view within the Church of Eighteen Eyes is that beings originating from Harmony — including those from its subplanes of Sustain and Refrain — are naturally invested with a soul, whilst beings from other planes may have similar manifestations, though they may not necessarily be souls.

Origins & Destinations of Souls

Souls, being manifestations of the Song, are created beyond the Skein of Night and flow into Creation via the Cacophony. It is believed as well that, upon death, all living creatures divest their souls, which are individually guided by a Psychopomp, back to the Song to be "resung."
Though it is not considered orthodox thought, mage-scholars who have communicated with Psychopomps in the past have recorded that this process appears to be peaceful, sometimes happening immediately on death, and at other times taking years, decades, or even millennia for the soul to achieve peace within Creation to be resung. The Church as an institution views this process of destruction as a terrifying act, shreding away one's identity. Individual sages and priests differ in their interpretation, with most within the cults of Old Lady Loom seeing it as a natural and beautiful process.

The Saved

Some souls are "saved" by individual Gods which take notice of them, and they are whisked away to a particular realm within Symphony to serve that God. These souls may serve their God in whichever way the God wishes, including being reshaped into angelic beings (though this is not necessarily the only way an Angel can be created). This is considered a miraculous thing to many.

The Stolen

Further, souls can be "stolen" by a Demon that — through some means — has its claws within the dying individual. Souls stolen in such a manner may simply be devoured, with their power invested into the form of the Demon, or converted into that or a Devil. It is unclear why some Demons appear to twist souls in such a manner, though it is theorised this is because a soul is a particularly "pure" manifestation of the Song, and therefore utterly disgusting and inimical to Demonkind.

Lost Souls

Though Psychopomps work tirelessly to "recycle" the souls of the dead, not every soul can be so lucky, with many becoming trapped on Harmony for one reason or another. When such occurs, the soul often twists, becoming a Ghost or other form of disembodied Undead.
Scholars and theologions have debated for centuries over the nature of Undeath, as it was once believed that there are as many Psychopomps as souls within Harmony, one per soul. However, this would not explain why so many souls appear to be "missed." Some believe that there are a fixed number of Psychopomps, yet no limit on the number of souls. Some believe a malevolent force is devouring many Psychopomps at their source within the Cacophony. Others — heretics in the eyes of the Church — believe that the Disjunction fundamentally broke the balance when the souls of mortals were "copied," though some go so far as to claim a soul cannot be copied, and those descending from Refrain and Sustain are thus soulless (a view point hotly rejected by the Vekhen-aligned Church).
Whatever the cause, Undeath remains rife throughout Harmony, with more and more souls becoming lost within the world.

Type

Metaphysical, Elemental