Enhanced Magic (3.5e Sourcebook)/War in D&D
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 War in D&D
"Men go to war and expect mages to fight, then abandon them when the going gets tough. I am here to make sure when the break and run you know what to do and don't get yourselves killed." Tarneth Silveron, Elven Battlemage
Combat in D&D is very common, since most games are about adventuring. Almost every adventuring group will go through periods of gritty combat; fighting monsters, aberrations, even other hero type characters from time to time. And while this helps to test the groups mettle and help the caster types to discover exactly what can be very useful for combat purposes this in itself will not prepare any caster for service in a wartime environment. On a war front most, if not all, caster characters will find that their spells either run out before the fighting does or the fighting is ended a lot faster than anticipated. During a war confrontation if the fighting is ending quickly that means one side is being overpowered. If one side is losing badly this can result in a full on slaughter. When men are running as fast as they can and casters are deep in concentration they can quickly find themselves surrounded by foes. In this sort of event the caster can find himself in immediate danger, as powerful casters may have inflicted the majority of losses on an opposing force. Also in any warfront the player will be faced with a new type of challenge - the challenge of facing the hordes. While most people like to think that the fifty level three warrior archers aren't a threat remember two things; one as a caster you are squishy and that fact never changes much, and any time you take damage it is much harder to get spells off. Two that quantity has a quality of its own, with fifty separate attack rolls even if they require natural twenties to hit expect at least a couple to do so.
The key considerations for casters in a wartime enviroment will be based upon their area of expertise. Most battle mages tend to be directed energy casters, so they will need to focus on survival in an up-and-close combat situations and figure out their best mitigation spells and when to enact them. If the spell expires prior to fighting it won't be of much help to the magic user, and it is equally bad to be caught with your proverbial pants down if you didn't bother with mitigation prior to the fight going badly. Other caster types particularly those that focus on summoning are slightly better off since they can erect a wall of meat shields while they make their escape. Even enchanting can give you a short term minion to defend you while you make a good escape, though the defensive aspect should not be ignored for these mage types either. Particularly strong enemies can either resist or quickly destroy the things you put into their way while you make good on your escape plans.
 How to Survive in War Centered Campaigns
"Any military action will have an ebb and flow much like magical power. Each of you will need to understand and recognize this flow to put yourselves in the best position. If you fail in this you will be dead, and likely no one will remember you." Vrass, Mage Tactician
Magic packs a serious punch in the worlds of D&D however you will see that once your spells run out serious problems occur. While mages do have a wide selection at level twenty how many times do you use a second level spell against something that is going to cause you more than irritation? The common conception of the wizard in base 3.5 is you are a “glass cannon” and once all of your most powerful spells are gone you are effectively annoying the enemy instead of causing any serious damage. In any campaign where you reach higher levels things also become extremely hard to kill with spells as they start gaining resistances except for those rare occasions you cast an instant death spell and the creature you are fighting fails the save (which if you are facing appropriate encounters is unlikely at best.)