Krdytkyu

Magic is derived from the energy field surrounding the world. A mage accesses that field through incantations to perform feats of magic in the physical world. Most magic is temporary, and can only last as long as the incantation is being performed. However, there is a way to capture the magic permanently so thst it doesn't disappear back into the field. This is done by creating runes, which are a set of sigils that keep the magic contained in whatever physical material they are made on.

Runes are the basis of technology, and used for many purposes, including the construction of armor. Magic armor is used in warfare, and is created by inscribing runes into the material during its construction. It can have different attributes depending on the runes inscribed, such as increased strength, defense, speed, and so on. The kind of material to create the armor also matters, as different materials work better with certain runes more than others.

Even though mages can create this kind of armor, they cannot use it themselves. Armor made with rune magic disrupts their own ability to access the energy field, preventing them from using their own magical abilities. Therefore, they are forced to depend on conjured weapons or shields to defend them, or platoons of soldiers to keep them safe in combat.

Why would this be the case?

Magic creates an Aura, much in the same way that electricity creates a magnetic field. When casting a spell, you create a burst of aura, but a Rune creates an aura for as long as the Rune has magical energy. This aura affects the magical field that sorcerers draw on for their spells in much the same way that magnetic fields can affect electronics.

The implications of this are interesting.

• As each sorcerer casts a spell, they "pollute" the energy field around them, as well as thinning it. Thus inexperienced sorcerers may have to wait for a few seconds between spells, even if each one doesn't use much energy, to allow for the local area to settle again. Skilled sorcerers could thus rapid-cast more effectively, using their increased skill to counter act the pollution caused by repeated spells.


• The more enchanted a piece of armour is, the greater the Aura. Thus heavily enchanted handcuffs can be used to detain sorcerers, and skilled sorcerers may be able to function whilst wearing lightly enchanted armour.


• The effect of a magical Aura on the Energy field will take time to recover, this can allow sorcerers to track other sorcerers and enchanted items by the disturbance they have left in the magical field.


• (from XtremeBaumer) Enchanted armour/weapons could interfere with with one another due to their Auras. This will likely only occur at very close proximity, such as grappling or striking enchanted armour with an enchanted blade (due to attenuation from distance like magnetic fields) but could allow particularly strong enchantments to overpower weaker ones. As your sorcerer would be wearing the armour, they are thus suffering much worse interference than they would just by standing next to a guy wearing it.

Sorcerers tap mana from their surroundings. Despite being thinner than air and invisible, mana is still a fluid that can and will be blocked by a metal plate.

Wearing armor or heavy clothing reduces the body exposure to mana and weakens spells. A sorcerer's robe is usually made of silk or some other light cloth that does allow mana through for bigger fireballs, which is why all those elders with loreal'd beards like to wear a gown for all occasions.

You have answered this yourself, "Armor made with rune magic disrupts their own ability to access the energy field, preventing them from using their own magical abilities."

My Answer - They could

They could get around this by switching the armour off to cast magic and immediately on again to protect themselves. This is how sword fighting works. It's an alternation between attack and defence.

This sort of magical shield is used in Robert Jordan's Wheel of Time series.

I'll imagine two mechanisms for doing magic-

1). The mage draws energy from the field into them self and the projects it back out to create the magical effect

2) The mage draws incoherent energy from the field toward them self and then focuses and directs the energy into a coherent beam or patten to create the magical effect.

I'll address 2 first. In this mechanism, it's appropriate to imagine the mage as creating a " low pressure" zone near them self and then creating complex and subtle distortions that act as a lens to focus, shape and redirect the flowing energy (initially flowing from all directions toward the low pressure zone). In this imagining, there are two ways for magic armor to interfere with magic: first, such a full body layer of positive magic all around the mage could counter act the mages ability to conjure the negative flow needed to start the spell. Second, the refocusing of moving magic to create an effect requires an astoundingly subtle and complex lens. This lens manipulation ability is what really separates great experienced mages from novices. The presence of any magic in the matrix of the lens is going to change the dynamic of lensing the flowing magic. For complex and subtle magic, a mage would want a casting zone as free as possible from magical noise that might create defects in his lens. We can see how being wrapped in heavily enchanted ridged magical armor could badly distort the magic lens and prevent the mage from focusing the energy as needed to create the magical effect.

You can imagine all sorts of other magical device limits / aides resulting from this mechanism. Not spelling them out cuz I'm texting this and my thumbs wearing out.

Mechanism 1 seems to me to result in more of a partial block to magic than absolute. In this case we imagine the mage must open a physical channel to the field and stream sufficient energy into their own body. Great mages only include those who can draw and hold huge amounts of energy without killing themselves. As above, head to toe armor could simply block the mages ability to open the channel. However, just leaving ones arms or other surface unarmored, and hence unblocked, would seem to remedy this. At least, one could draw in energy in that case, just more slowly due to the reduced area of the collector.
The slow draw rate could be a problem for spells so powerful that the mage actually can't draw the full energy required for the spell into them self prior to beginning outputting it to create the spell effect. Imagine a lightning bolt. The spell caster draws in magic rapidly. Once he has enough to overcome air resistance and create an ionized channel between him and his target, he releases the energy to do so, then he continues to rapidly draw in and dump out energy in the form of electricity into the ion channel, causing damage to the target and preventing collapse of the ion channel. The mage can't draw the whole energy supply for this spell in before beginning because it would burn him to a crisp. However, if his ability to draw energy quickly from the field is retarded by armor, he could open the ion channel, but then see it collapse because he can't feed electricity into it quickly enough to hold it open.

So, with this imagining, there are lots of spells that are impossible while wearing armor - particularly those needing big energy levels and or prolonged streams of energy flow. However, there are also many magical effects one would imagine being possible in armor - particularly if the caster is wearing modified armor that leaves collection and casting areas on his body unarmored and unblocked. Yes, the casting time for these spells might be significantly longer, but they would still ultimately be possible in armor.

Hopefully, you can find inspiration in these two scenarios that give you justification for the limits you want to set and also allow you to weave some deeper consequences and effects that make the world your creating richer and more layered.

You can. You just can't cast any other spell while wearing it as you already are inside a spell.

Casting a fireball (for example) would result in creating fireball between the caster and his armour. Which don't have directional doors that would allow fireball from inside to escape. One grilled ex-wizard to go!

Casting second spell to create an opening in armour to cast third one is counter productive as it mean there are spells that negate armour (you don't have to attack to deplete the magic armour you cast opening and stab the guy with a fork). Also casting second spell to cast third one would create time consuming stack that could be used by enemy. "Hey, he's casting opening in armour, quick, shot him in there with a crossbow".

and because mages are mages they prefer to be able to cast a spell, conjure a familiar o magic weapon on the spot rather than ask Robin of da Hood "give me a sec to take of my crakow of speed".