Magic is the phenomenon where mages use their mana to interfere with the world, a method that allows apparition of phenomena by giving appropriate stimulation to the point of application.
Modern magic is achieved through technology Operation Orb, unlike the era of legends, this allowed people to clearly understand in detail the where, the how, and to what degree of power to interfere with reality.
Some of the aspects of magic in Youjo Senki's universe are noted to be a mystery such as fundamental principles related to mana and interference spells.
Mana signals can be detected by using magic, and it seems most artillery forces in this world have equipment to detect mana signals and conduct magically guided bombardment. In Rhine Front, a number of Imperial recruit mages got blown away in trenches by Republican artillery because they leaked mana signal by deploying magic shield.
In the olden days magic was accomplished with various magical devices, where the user have to turn chemical reactions happening in nature to equations and reproduce them with their will. However, before the Industrial Revolution, the old-fashioned devices used by magicians are inefficient in comparison to their modern counterpart. They are also unlikely to be produced in large numbers.
Magic started to evolve after the Industrial Revolution when mages took the concept of a computer from the Differential Analyzer to be replicated by magic. Giving birth to operational orbs that made composing spells more convenient and efficient, which lead to standardized and uniform spells used by mages.
Main Article: Operation Orb
A tool used by mages to recreate miraculous phenomena through the combination of mana and analog calculation. Modernized magical devices that excelled in speed and efficiency, born from taking the design concept of the computer and compact pocket watch.
Scepters are tools mages use when casting spells, rifles are the substitute used by modern mages. Rifles are mainly used as a tool to cast long range spell in battle. A few highly skilled mages like Tanya von Degurechaff can fire their spells from their fingertips.
In Youjo Senki's universe spells aren't a set of words, spoken or unspoken to invoke some magical effect. Mages have to understand how the phenomenon of spells they intend to cast works to recreate the deeds such as miracles. The same way people understand how to light a fire with a lighter, thus enabling them to recreate the deed through magic.
The aeronautic magic, which allowed mages to soar through the sky. This magic works by creating propulsion, forcefully raising a mage into the sky, and maintaining balance while in the air. The standard altitude for flight mages is 6000ft, and it's not recommended for them to propel themselves any higher using this spell due to thin oxygen and massive amounts of mana their orb has to bear to maintain flight. Surpassing these limitations need a multi-core orb.
- Passive Shell: Protects against small fragments, small caliber bullets and blast waves. Can be kept on indefinitely, also easy to cast together with other spells.
- Active Barrier: Increasing the density of the shell in one part to create a shield that can withstand machine gun fire. Whether it provides adequate protection depends on the mage's skill.
- Enchanted Rounds: Sealing spells inside bullets or grenades to activate as required. Spells can be activated with minimal mana, but the rounds need to be prepared.
- Homing Cluster Shot: Any bullets that imbued with this spell will split into several homing projectiles upon reaching a certain range and will seek out the target.
- Artillery Shots: Any bullets that are imbued with this spell will have its firepower enhanced to be comparable to artillery shots.
- Optical Spells: Emits a straight heat beam. Skilled mages can refract it to change its course. Noted to be the favored spell of Republican mage for their volley of fire doctrine.
- Explosive Spells: Creates an explosion at any coordinate.
- Self-Destruction: Overloading one's Operation Orb with Mana causing it to reach critical mass and explode, injuring the user and surrounding enemies if not outright killing them.
- Guidance/Interference Spells: Directing a spell's trajectory, could be used for offensive and defensive purposes. It also could be used to interfere with radio signals.
- Enchanted Bayonet: A bayonet imbued with Mana sharp and durable enough to cut a man or plane in two. Even a tough magic shield can't bare the attack of magic blade.
- Optical Decoy Magic: Creates an illusion that will interfere with the visual senses of those around the user when cast. Skilled mages can easily differentiate between what is real and the illusion, especially since this spell is inclusively targeting sight and nothing else.
- Scanning Magic: Processes data of a Mage's surroundings, uses vary from locking on target coordinates, detecting observational waves, and analyzing an enemy's mana signature. In the anime, this spell takes the form of a holographic screen while in the manga it's akin to a halo above the user.
- Of all magic spells in Youjo Senki, the fundamental principle of Interference Spell is noted to be not fully understood as of now.