Castles are an easy starting point
Hmm, I'd probably go with castles being made of something like the black stone of Orthanc, and say the Force fields are for really important things. Nukes might potentially damage this material, but it's not a sure thing. Tactical anti-nuke defense would mainly be spells that shoot them down, force them off course, or even teleport them back where they came from.
I like all this, but I would go with big dragons for hypersonic flight, and a general lack of heavy air support for the fantasy side, with things like homing spells from wizards for anti-air capabilities.
Here's a little blurb on the different types of magic I dreamt up for this. This is just me spit-balling, and can be revised as needed. All fantasy humans (henceforth "fumans") can learn these, and even more than one at a time.
So, the first types of magic I'm giving the placeholder name "Death Magic." There is power in death. When something dies, especially something intelligent, something leaves this world, and something else enters. This something else can be consumed by those with the right training, and used to enhance their strength, body and soul. This is the magic used by warriors and knights. It's based not only on kills, but martial skill and experience. Knights tend to be those strong in this magic, and typically gain their knighthoods based on their martial prowess. This means that for people to earn, and even lose knighthoods is more common than it was in real life, and knights have to ensure their sons are raised to be skillful and useful to the crown in order to safeguard their birthright. Fortunately for them, it is possible for this power to be passed down from parent to child, though the child will have to "re-cultivate" it somewhat. However, this, combined with the great wealth and fine equipment that knights tend to have, means that an intelligent and conscientious knight house can secure their future fairly easily.
This magic grants enhanced physical abilities, including, but not limited to, enhanced strength, speed, durability, agility, senses,perception, and reflexes, as well as battle precognition (similar to Jedi), a danger sense (like spidey sense), a healing factor, and spiritual senses like the ability to sense the spiritual auras of living things. More advanced techniques include more esoteric abilities such as summoning swords of spiritual energy to strike opponents from afar, the ability to harm opponents on a spiritual level, short range "flash-step" teleportation, phasing, and much more.
There is a power in the simple things of life, a job well done, a meal well made, a field well tilled, a life well lived. The wise can hold this power in their spirit, and then project to out into the world in constructive endeavors. This is the principle what I'm giving the placeholder name "Simple Magic." This is the simplest to learn, but the hardest to master. It's the most common work-a-day magic that most ordinary people know at least a bit of to help with cooking, cleaning, farming, healing wounds, dulling pain, and other simple tasks. At the higher levels though, this magic forms the basis of advanced area healing spells, and the creation of powerful magic tools and weapons. The greatest masters of this art use it to forge weapons capable of summoning storms, striking down mountains, and splitting the seas.
Before the birth of creation and its myriad realms, the creator of space-time itself, a powerful god, was struck low. His blood was scattered throughout many universes, where it congealed and hardened into a substance called Rift Stone, made not of ordinary matter, but microscopic rifts in space-time itself. This substance is the basis of the two magics that follow, which I'm calling (for now) Alien Magic, and Thought Magic.
Alien Magic is achieved by taking Rift Stone, grinding it into a very fine powder, and then injected traces of it into your own body over the course of your entire life. The basic technique of Alien Magic is to open conduits to other planes of existence, containing totally different laws of nature and spiritual powers. One then draws on the power of these other realms to perform a variety of powerful, and bizarre feats. This is the most "Wizardly" magic that does all the flashy and versatile stuff. Over time, use of Rift Stone in this way corrupts the body. This corruption follows four stages, that progress depending on the speed at which the mage progresses their skills.
In stage 1, the user is uncorrupted, and appears quite normal. This stage tends to last from 2 to 20 years.
In stage 2, the user grows deathly pale, and they develop permanent dark bags around their eyes which begin to sink into their skull, and glow with a purple light, the user's hair also tends to grow longer, and begin to billow in unseen breezes. This stage tends to last from 20 to 30 years.
In stage 3, the eyes have completely sunken into globes of fire, and cracks that show a window into a brilliant night sky begin to appear all over the user's skin. The hair transforms similarly to these cracks, and now permanently waves, like a slow flame, or a flag. Most users die from their bodies failing after just 3 to 15 years, but a rare few see their bodies adapt to the changes, and progress to the final stage.
In stage 4, the mortal body is completely gone, and the wizard has become a pure living crack in reality itself. In this stage, users are often so powerful that merely being in their presence is dangerous, and thusly they withdraw from public life into research. After a few decades of this, they invariably withdraw into a pocket universe of their own creation, and devote themselves to the contemplation of infinity, gradually losing all contact with civilization.
Thought magic is developed differently. Instead of injecting Rift Stone into the veins, it is baked like charcoal, and burned similar to incense. The fumes are then breathed in over a long period, granting those who breath them vastly expanded mental powers (similar to mentats from
Dune), as well as incredibly telepathic abilities. Allowing them to coordinate activities across realms. It is possible to learn both Alien Magic and Thought Magic, but it is highly dangerous, and many who try see their bodies and minds tear themselves apart.
The final, and most difficult form of magic is Arithmancy. It draws its power from the Monad, the metaphysical source of all mathematics. Arithmancers dedicate decades to contemplation of the Monad, and all branches of mathematics. Eventually, they can develop powers that shame all the other magics in their sheer scope, manipulating mathematics itself to warp reality with no regard for the limitations of space and time.
