Biologically immortal

Spirits are Energy Beings. They are born from the raw energy released from the Soul when someone dies – the energy that would normally be captured by Seraphim and remade into a Ghost -- but only when at least a dozen beings die near-simultaneously and within a reasonable distance of each other. Their physical appearance becomes a blend of those of the beings the souls originally belonged to – including their clothing, which is technically part of the spirit's body – with the exception of the slight translucence inherent to their structure, and their eyes, which always lack pupils and give off a slight glow.

The physical and mental ages that a spirit begins their life at vary. Both are sometimes influenced by the souls they are made of, but there is always a randomness factor that makes the spirit's final personality difficult to predict. The original souls offer up some basic memories about how the world works and how to take care of themselves, so a spirit is never left helpless at birth.

Spirits have all the powers that come with having a body made of energy, including passing through solid matter and levitation.

While the life of an immortal being can be crushingly lonely at times, it is often improved by a spirit's Trusted.

It is said that spirits who do meet their end are claimed by a bleak and empty world called Danketsu, where they will only find true happiness if they manage to synchronize their death with that of their trusted.