In traditional fantasy battles, you have 2 large armies charging at each other while magic users on both sides throw out various spells for whichever side they are on like supernatural artillery. But in more modern times we really have pitched battles. In addition to that we already have powerful ranged weapons so using magic in its traditional role isn't necessary. So how would you would use magic users in modern-day battles?
Suppose you have a war with both sides having modern weapons and using modern tactics. Both sides also have access to magic users. The magic users powers include:
1.summoning a storm ranging from a small drizzle to a super storm.
2.summoning a magical creature like a dragon, sea serpent or elemental.
3.banishing magical creatures.
4.the ability to increase the probability of a certain outcome, such as changing the probability of winning the lottery from 1 in 100000000000 to 1 in 10.
My question is, how would this power be used in modern war tactics and against modern weapons? Or are they too impractical to be used at all?
The power of an individual magic user depends on his emotional and spiritual state at the time he is using magic. Some people are more spiritually inclined to use magic than others and the more you use magic the easier it is to use it; like any muscle, the more you use it the more powerful you get. I'd say for storm summoning apprentice-level magic users probably summon a powerful storm including lightning and tornadoes but they probably wouldn't be able to make a storm the size of a hurricane for example. At mid-level you might see a magic user summon a storm the size of Hurricane Katrina. At the supreme level you could probably summon a super-storm several times larger than Katrina (there aren't that many supreme level magic users, I'd say less than 10 for each nation.)
Distance is also a restraint on a magic user. An apprentice would only be able to summon a storm where he actually is. An intermediate might be able to summon a storm that is several miles away although he would still have to be fairly close to where he wanted it to appear. At the highest level you can summon storms from just about anywhere on Earth. But even at the highest level it would take a long time (maybe a couple days to a week) to summon a storm beyond 100 miles from where you are.
Of course this may vary because an apprentice for example might for some reason find himself in the heightened spiritual state which case he would be significantly more powerful than normal. Or for example a magic user at the supreme level who is still mourning the death of a loved one might himself temporarily reduced in power. The same goes for the rest of the abilities. It's magic, not science so I can only really give you generalizations.
Ok, let me explain how the system works. The magic users here are people with a special spiritual connection to an higher dimension. While they are capable of doing all of the powers listed above they usually specialize in one, maybe two. Most start learning from a young age. So there is a fair amount of skilled magic users on either side.
As far as rules go there are just 3 simple ones.
The farther away you are from where you want to use magic the more time and/or skill and power it takes to perform it.
Your spiritual and emotional state can also decrease or increase your connection to the higher realm and therefore your power.
The more a magic user has practiced, the stronger the connection is to the higher plane and the stronger the power is.
Using magic requires spiritual energy. It's not physical energy so it's not going to make you tired or hungry, but using too many spells in a row decreases power slowly until the user is unable to use magic for a short period of time (a couple of days to week); however, intermediate or higher level magic users can use a special form of meditation to shorten that time (fully recovering the magical energy in a couple of hours). The amount of spiritual energy that a person has depends on the overall power level.
Magical creatures, while still physical, come from completely different dimensions than ours, which means that they cannot be killed with conventional weapons. However they can still be injured and incapacitated with them. They can also still feel pain. To put it in more practical terms, if you shoot a magical creature in the face you won't kill him but he will probably retreat and heal for a while. When he does come back here he will probably try to avoid attacking you again because being shot in the face really hurts. The only way to permanently get rid of a magical creature is to either banish it or kill the magic user who summoned it.