I love the fantasy genre so much, and immerse myself with it a lot. But I’d first like to say that I like litppunk’s ideas and views. It actually gives a good insight or base to work with.
Anyway, a lore explanation of ghosts, spirits, phantoms, etc. could be that the “natural” ‘flow’ of this world (a disturbance in the force, lol) meaning, time and space not to mention reality has convoluted so that things that were dead with a strong will could disrupt the “natural” of the world and anchor themselves as a “force”. This being said, it technically could also mean that the dead aka ghosts are pretty much in a state of “semi-reality” where they don’t exist but at the same time they do exist.
But that being said, I don’t think that spirits should all be hostile, hell, maybe you could form a “contract” with them in exchange for supernatural powers on par with mages.
Also, I think those with an inclination to magic would drain their “mana” from different sources, and have a limited amount of uses. Normal mages draw from the atmosphere, but those with a more darker inclination would draw from living things. I’m thinking you could even have those who are more inclined to a certain element, dark, light, fire, water, etc.
Some are blessed to be able to use all elements, some have a massive mana pool, while those who can only use one type excel in that, or those with a low mana pool learn to use their mana more efficiently. However, those with no inclination towards magic can’t use magic that can be projected outward of their bodies, but maybe they can enhance their own physical and mental abilities instead.
I like to think of a “gate” those with gates, one can use mana to project magic through their gate outward into the world. However, those who lack a gate cannot project mana outwards, but can only manifest it inward. So those with a massive mana pool but no gate could simply be a great warrior. However, here’s where spirits come in. Those who are in a contract with spirits can use THEIR gates, or simply themselves as a medium to project their powers. Of course, those with no magical inclination or mana capacity whatsoever could still use the spirits powers instead.
I’m thinking of more stuff to add, but it’s 3:48 am and texting all this out is tiring.