On a basic level, symmetrical warfare (where two sides line up on a field and attack) is governed by a lot of recognized principles and tactics, like envelopment, flanking, retreats, charges, and routs. For my world, I wanted to approach warfare differently by introducing two twists: first, magic is incorporated into combat, and second, killing people is forbidden.
The reason I wanted combat in my world to be non-lethal is because death in my world functions differently from other fantasy worlds: rather than being sent to a vague and mostly opaque afterlife, people know that their souls will be expelled from their bodies and doomed to exist in a half-conscious state here on earth, constantly craving the things that drove them in life. The world, as I imagined it, is already suffused with ghosts who are tied to familial obligations as guardian spirits or left to aimlessly wander. Meanwhile, the living are obsessed with living forever and extending their lives. Warfare, then, has to be shaped around this institutional fear of death.
With that in mind, I took some notes on how I envisioned warfare would look in my world:
“Killing your opponent is taboo, and a violation of the rules of war. Instead, your focus is to incapacitate enemies and capture them. Mortal injury (including cleaving off limbs) is fine, as long as the person does not die. Capturing can occur after or during the battle, but you must keep enemies from rescuing their own allies on the battlefield and bringing them back to their lines.”
“Armies are not made of professional soldiers, and are instead peopled by a mix of militias, career soldiers (like samurai), and mages. Mages form the heart of each unit, which can range from 5 people to 50 people. There is no external organization to the forces, and armies are loosely commanded by a war council.”
“At the periphery of the battlefield are healers and enchanters, who support the army by healing the injured (both friendly and captured enemies) and enchanting their allies with spells that prevent physical or magical damage. It is not permissible to attack these healers or support mages, but it is permissible to capture them without violence.”
“Honor is one of the key constraints of combat. Those who do not obey the rules of combat are stigmatized and punished harshly. It’s dishonorable to try to escape once you’re captured and held by the enemy. False surrenders and disobeying parlay rules are also forbidden. Everything else, including sabotage, spies, subterfuge, torture, hostages, and ambushes are permitted but looked down upon.”
“There are different kinds of mages. In my mage hierarchy, wizards are elites. Sorcerers, illusionists, witches, and hedge wizards are all lower on the hierarchy. They can be very specialized and even more capable at certain tasks than wizards, but they are not as all-around powerful and adaptable as a wizard. Mages can use any magic they want, as long as its non-lethal.”
“There are three kinds of magic: spoken magic, similar to chanting or shouting, movement magic, similar to martial arts kata, and written magic, which is made of spell maps imposed on skin or objects. There does exist anti-magic measures, which are dependent on the kind of magic being used. For spoken magic, anything that disrupts speech or sound can jam a spell. For movement magic, anything that restricts the necessary movement of the body (arm and leg movements, etc.). For written magic, contact has to be made with the written surface to jam it or break it.”
“Other rules:
1. Biological warfare is not allowed.
2. Healers must do everything in their power to keep enemy soldiers alive, as well as their own soldiers. In case of a conflict, friendly soldiers take precedence.
3. Psychological warfare is permitted.
4. Captured enemy soldiers must not be allowed to die, even after the battle is over. Their well-being is entirely entrusted to their captors, who are honor-bound to keep them alive.
5. Sieges are permissible, as is the capture of non-combatants. In the case of sieges, the attacking army may impose conditions upon a community that will result in eventual death—cutting off water and food supplies, etc. It is up to the community to survive or surrender.”
“Since death is taboo, lethality is not permitted in warfare. Incapacitating an opponent through cunning or strength is mandated, with capturing an opponent being the ultimate goal. When enough units are incapacitated and captured, a victory is declared. With these conditions, individual bravery and recklessness (since there is no chance of death) is much more common than normal. Ransoms are paid to reclaim captured combatants, which enrich the capturing parties’ individual families and bring them prestige.”
“Armor, wrestling, blunt weapons, and physical strength (the ability to induce trauma on a body) are key components to normal warfare, with individuals attempting to incapacitate one another via melee being the main method. In addition to this, magic comes into play as safeguards and offensive tools: almost all mages and combatants have some kind of enchantment which limits physical or elemental harm, such as draw-redirect or targeting with ranged spells (without touch). To overcome these magical defenses, physical touch is required to make interface with another being, and hand-to-hand combat is highly prized as a final execution method to incapacitate an enemy.
All of this results in combatants and mages wearing extremely comprehensive, full-body armor and weaving heavy enchantments around themselves. Ranged attacks in general combat are generally meant to “jam” enemies’ enchantments and “soften” them for melee combat.’
“Armies are generally made up of family or familial alliance units, individual vagabonds, bands of companions, and mages and their entourages. The center of every unit is a mage, with each having their own specialty. Armies are usually below 1,000 units and are commonly 80-200 units, with a council of warleaders representing their constituents. Actual warfare is very loose and chaotic, with routs and intimidation common. Mages and strong soldiers form the morale center of their armies, and have the essential ability to rally their forces with their bravery or cunning.”
“Every battle can become extremely chaotic and changeable, since mages can employ almost any tool in their magical arsenal to turn the tide. Illusions are common to try and fake out enemies, as well as techniques that alter or disrupt the field of battle. Diseases are against the rules of war, but fire, water, earthquakes, light, animals, and extreme force are permitted as long as they are not lethal.”
“Ghost warfare is also an integral part of warfare—ghosts are martialed and invoked to protect their families and assist them in battle, which can take the form of weather, physical manifestations or possessions (including golems and mannikins), decay or weaving of spells. Ghosts can be unpredictable and hard to combat, and so a channeler/sorcerer or necromancer is generally a major asset in large-scale warfare.”
“Horses and cavalry are generally avoided because of horses’ ease of being incapacitated or frightened by ghosts, magic, mages, or illusions. However, they are utilized for fast travel and mobility.”