Every human is born affiliated with one of seven elements. This element determines very little for most people - it's a trick of the soul. However, when somebody undergoes intense trauma, sometimes, the powers affiliated with that element will unlock as a protective mechanism. Often this unlocking is violent; sometimes the Elemental in question won't remember getting their powers because of the associated trauma.
Core Elements are those corresponding to the four elements in nature: Water, Earth, Fire and Air.
Active Power: Invisibility
Passive Trait: Fast healing (at the very high end of normal range - bruises and scrapes often barely register, scabs appear quickly, etc.)
Unstable State: Uncontrolled reactions in nearby water (a specific elemental will freeze or boil it depending on their personality). It is more difficult to drive a Water elemental to instability than Fire or Air. Stabilized instantly by an Air or Salt elemental or more slowly through controlled breathing, etc.
Active Power: Telekinesis (moving objects around mentally)
Passive Trait: High natural strength (high end of normal range).
Unstable State: Quaking/shaking of nearby objects, at extreme end localized earthquakes. It is much harder to drive an Earth elemental to an unstable state than Fire or Air. Stabilized instantly by an Air or Salt elemental or more slowly through controlled breathing, etc.
Active Power: Pyrokinesis (lighting fires through psychic power)
Passive Trait: High body temperature (within normal range but at the high end; often fluctuates depending on mood)
Unstable State: Uncontrolled fires and/or explosions; stabilized instantly by a Water or Salt elemental or more slowly through controlled breathing, etc.
Active Power: Wingless flight
Passive Trait: High agility and speed (high end of normal range)
Unstable State: Air pressure instability - area close to them will fluctuate in pressure; stabilized instantly by an Earth or Salt elemental or more slowly through controlled breathing, etc.
The Celestial Elements correspond to the three celestial elements as put forth by Paracelsus - in which all poisons came from the tria prima, and the three elements also represented the body (salt), the soul’s emotion and desires (sulfur), and the spirit’s imagination and moral judgment (mercury). These three elements are much rarer, more powerful - but also more dangerous.
Active Power: Telepathy (reading and communicating mentally)
Passive trait: Eidetic (photographic) memory
Unstable State: Uncontrolled suggestions and intrusive thoughts. Stabilized instantly by a Salt elemental, or more slowly through anti-anxiety medication, controlled breathing, isolation, etc.
Active Power: Shapeshifting
Passive Trait: Long lifespan, and resistance to most diseases. They can be killed, but natural causes tend to pass them over especially with how slowly they age. Also intensely charismatic.
Unstable State: Prone to psychosis, and can affect the perception of reality of those around them. Can only be stabilized by a Salt elemental or through medication/therapy/etc. (administered by somebody fully aware and accepting of their powers) over time.