It's an interesting idea. It is not incompatible with where I'm going, either.
Magic is ruled by primitive/elemental forces. (It's funny because I spend my time trying to reduce that set of forces and here you are trying to add another set.
)
Each of these has a positive and negative form and are related to other base energies... and not necessarily in the way we understand them in our world. For example, one scenario I have has gravity and electricity tied up in some kind of 'opposite but related' scenario... but I digress.
In that sense, heat and cold are polar opposites. In our physical universe, we don't consider cold a "thing". It's a lack of a thing. But in Mythruna magic, it makes sense to think of it as a thing because of the way heat can be manipulated. You have heat sources and heat sinks... and heat sinks can suck the heat energy right out of the air or anything really (converting it to some other form that may not be tangible on this plane). It may appear to break the laws of conservation.
So in Mythruna, you really can create cold.
Likewise, life force is an energy (likely a complicated tapestry of other energies) that can also have a complicated polar opposite. (This is the realm of the necromancer by the way). If you have excess life energy then you can impart it to something else. Remember that it's a complex array of other forces so it's likely extremely difficult to create on its own... but that doesn't meant that you can't impart your own energy to deficit or temporarily store some up.
However, because of this idea, there is a sort of "death energy". It's the life sink and it's likely just as complicated to construct as life energy... but as said earlier, this is where a necromancer plays.
Dead/rotting corpses are life-neutral... which is more unusual than it sounds. Even rocks can conduct life energy but something that was a live and is now dead can no longer do this. The stronger the original life force the more of a vacuum they leave but it's essentially stable. (Handling a dead body won't make you die or lose life energy... but the corpse will happily suck up and nullify any that you choose to project into it. Normal sentient life forms are naturally life-force-stable also.)
Any symbiotic life-givers will suffer negative effects from this relationship. For example, if there is some magical forest grove somewhere with an abnormally high life force, staying there may heal you faster. In Mythruna-magic-theory, it's also slowly sapping life energy from that forest but in general the forest is large enough to recover once you've healed and stopped sucking it away. Several dead bodies might tip that balance as they will readily suck up the extra energy (delivering it to the spirit plane most likely). Since the forest is not life-force-balanced, it could kill the forest over time.
(The job of a necromancer would be to depolarize and unbalance some of these energies but that is beyond the scope of this discussion... suffice it to say that fighting the animated dead potentially comes with additional consequences.)
There can be other ways this balance might be tipped. And corpses may be attractive to other types of magical entities for a variety of other reasons... not the least of which is their existing residual conduit link to the spirit plane.
Even in addition to spreading disease and attracting carrion... there are lots of good reasons to dispose of your bodies. But the carrion is not to be taken lightly. "Do you want ants? Because that's how you get ants." Only in Mythruna, the ants are 1-2 meters long...
Whether I can implement all of that or not, some of it is just window dressing on the basic idea that there are "energy fields". This is separate from the blocks and are closely related to water, smoke, fire, etc.. It's an underlying principle to make magic more "physical". Even if I end up cheating and falling back on boring prescripted magic like "every other RPG" (tm), I will base the theory of that magic on manipulating forces. Example: if you want to cast a fireball spell then you need to create the fire energy, hold it in a ball (static force field), and propel it forward (gravity push). In Mythruna magic theory, shooting a cone of fire is actually a much easier form of magic since it's just a nearly uncontrolled burst of heat energy.