Context and concept
The Big Bang occurred and the stars started to form and go supernova spreading the elements that were within them far and wide throughout space. The solar system, including the Earth and the life upon planet Earth, is thought to be made of this star dust. In my world an additional element was formed that ordinarily can't be observed by humans, Metatron. It's a type of metal whose atoms are present in every living thing like how carbon is. The special characteristic of Metatron is that it reacts to and is manipulated by the thoughts of sentient creatures. When this happens the thoughts and the Metatron merge to form a new substance called Phantasm, which can then be used as fuel for supernatural powers.
These powers vary based on the thought used and the elemental affinity of the user. Certain thoughts correlate to certain elements and everyone has a base elemental affinity they lean towards. Although additional affinities can be gained through training, a person can only possess up to 3 affinities out of 14 possible elements. Alongside the elemental affinities are the elemental domains which are groupings of certain elements. While an individual might not possess an element affinity on one side of the domain, by possessing an element affinity on the other side of the domain they would still be compatible with using the first elemental affinity in techniques and attacks, albeit with less power than if they were naturally that elemental affinity in the first place. For example, if an individual possesses a water elemental affinity then they would be compatible with ice affinity techniques. Even though they aren't naturally a part of said affinity. Trying to use a technique with an elemental affinity where there is neither power nor potential is, while possible, uses considerably more Phantasm than simply sticking to one's own elemental potential.
The seven domains and the elements they contain are based on both the seven deadly sins and heavenly virtues. The way I have it set up so far is as follows: the base element which can be used uniquely from person to person. The sin as a type of limitation or a bane that should be avoided. The virtue as something that is encouraged for the power. A generic unique property to each domain.
The seven domains are :
Domain of animal and plant life
Users of this domain are especially feared as the organic life they create or manipulate can overtake another person's Phantasm powers and constructs by "devouring" them. This is done by converting the enemy's Phantasm into their own. Skilled users of this domain can even control their enemies directly through the same principle by converting the Phantasm in their enemies body into Phantasm they can control. While extremely powerful, users of this domain must have temperance. As devouring or controlling an amount of Phantasm beyond their capacity will cause the destruction of their organic focus as well as severe backlash in their own mind and body.
Base elements are animal and plant life with the sin to be avoided being gluttony and the boon being temperance. The ability to manipulate people is the unique property for this domain.
Domain of fire and poison
With fire that threatens to char them or poisons to corrode their being, users of this domain must practice patience so that they don't overheat or overdose on their own power. Such an attitude is rewarded by eventually becoming immune to poisons or using flames to cauterize wounds.
Base elements are fire and poison with the sin to be avoided being wrath and the boon being patience. I don't really have a unique property for this domain...
Domain of light and aether
The domain is about strengthening lifeforce such as making things burn brighter and hotter or make an object stronger and more durable. Users of this domain have the innate ability to share their Phantasm with others often through the form of healing or support techniques. Such sacrifice is not unrewarded as the amount of Phantasm expended will return multiplied exponentially. While powerful it is not without its risks and limitations. Users of this domain must be careful not to save up too much Phantasm than they can handle. Regardless of the power it brings, such avarice will only cause their own destruction.
Base elements are light and aether with sin being greed and virtue being charity or sacrifice. Healing or other support techniques (think stuff like boosting certain stats in a video game) are the unique power.
Domain of earth and metal
Users of this domain aside can instantaneously create weapons or items. While it is possible to create Metatron, it is generally considered not worth it due to the large amount of Phantasm it consumes as well as the incredible stress it puts the mind and body under. Objects if conjured out of pure Phantasm will deteriorate after a while like all Phantasm constructs, and will revert to their original state if it was a manipulated material. There is a way to increase their longevity and power, by giving or sharing these objects to others. While highly valued there is a great risk in using these abilities. Users of this domain must have a generous heart as the items or weapons shared in this way are still connected to them. An imbalanced emotional state or being filled with envy will cause the item in question to become a cursed object that harms its current wielder and drains them of their Phantasm. Often resulting in death for both parties.
Base elements are earth and metal. The sin is envy and the virtue is kindness or generosity. The unique property of this domain is the ability to create special objects that can be shared with others to become even more powerful.
Domain of darkness and void (negation)
Whether covering themselves in shadows or negating their presence, users of this domain are at their strongest when they are hidden or concealed. They can choose to further limit themselves by imposing restrictive rules on their abilities. While doing so will hamper them in some way, the greater the restriction the greater the power is gained in return. Many users are famous as exorcists who can negate and restrict not only their own Phantasm but others as well. They must be careful as being consumed by the lust for power and control over others will leave them unable to conceal themselves and thus vulnerable to attacks.
Base elements are darkness and void. The sin is lust (in this instance lust for power or control) and the virtue is a type of abstinence or self-restriction. The unique property is being able to purify others' Phantasm abilities.
Domain of water and ice
Users of this domain must have diligence and show great effort in using their techniques. Being lax in control and persistence will result in the elemental effects overwhelming them. Symptoms of water toxicity or even being frozen alive can occur if one is not showing a good work ethic in using this domain.
Base elements are water and ice. The sin is sloth and the virtue is diligence or persistence. I haven't come up with a unique property for this one yet...
Domain of wind and electricity
Considered the most arduous domain to use and master, users of this elemental affinity must learn to submit and show deference to let the power guide them into their techniques. Being arrogant enough in trying to bend the elements to your complete control will only result in your body being thrashed about or torn apart.
Base elements are wind and electricity. Sin is pride while virtue is humility or deference. I haven't come up with a unique property for this one either...
As you can see I'm having trouble coming up with unique properties for some of the domains. I'm also worried that some of the unique properties are not strong enough when compared to the others. What I'm looking for are ideas for the unique properties of domains that aren't specific to one of the elements inside said domain. For example I originally had the idea to make the domain of fire and poisons unique property be a cure for ailments. But I rejected that idea because only the poison element worked and wasn't a generic enough concept to work with fire as well. In addition if it's not too much trouble I'd like some feedback on the magic system as a whole. The overall concept as well as what could be changed.