Demiurge, the name given to a supreme deity, is an omnipotent entity of light who rules all over existence in which they have created.
An Angel is a celestial being under Demiurge that has inherited his light, which is imbued into their elemental energy, and has a naturally superior manipulation of soul energy. An angel carries a much greater amount of spiritual energy than phantoms, also known as humans, along with faster regeneration speed.
1 in every 100 spirits can become an angel, although chances may vary significantly with each region, planet, or universe.
For spirits that have not inherited the soul of an angel, they usually naturally lack the strength in spiritual energy.
Spirits have the ability to store or eat other spirits. Stored spirits can be freed once the host has been defeated or has lost more than half their soul energy. Eaten spirits will be absorbed and will cease to exist, becoming one with the host.
When spirits are inflicted with open wounds, their soul energy will pour out like blood. Wounds and missing body parts are capable of being regenerated very quickly -- in a matter of minutes -- depending on the circumstances. If a spirit's body is entirely destroyed, it can still be regenerated, but it's soul will be revealed, which makes the spirit more vulnerable to capture or absorb.
A spirit's soul is very essential. It is similar to a human's heart: without it, the spirit will cease to exist. The soul is an intensely glowing orb of light, located in the center of a spirit's body, which generates soul energy.
Angels, weak to superior darkness, are the holy and celestial human spirits that exist to purify the world of malevolence and work as the agents of Demiurge.
Phantoms, weak against demons, are human spirits that also rival the fallen. Some don't play much of a role in existence and can be neutral in terms of divinity or malevolence, although many side with the divine. On rare occasions, phantoms can still be very formidable and powerful, with powers matching that of a god's. Due to the phantom's lack of divinity, they are easier to be possessed and succumb to demonic energy.
Spectres are spiritual creatures, which are completely physically and mentally unrelated to human or human-like entities. They can resemble regular animals, or they can be otherworldly or mythical creatures such as dragons, phoenixes, or etc.
Demons, weak against angels, are the malevolent, much stronger manifestations of specters/phantoms, and can also be devil spawns. However, they must embody demonic energy, which makes them weak against celestial powers.
Dark angels, weak against superior light, are the betrayers of god, or ones that have fallen into madness from the malevolence and corruption of darkness. They are the biggest threats to existence.