Wind Guardian

Vance raised his warbow and fired. His arrow shot was true from the bow, but as soon as it entered the Wind Guardian's storm, it was thrown wild, up and to the left, and simply clattered to the ground. 
Rigana smiled as she held the Guardian. "Try again. Don't worry about hitting me, I can also cast a true shield if you manage to aim it right."
Vance lined up his next shot. If the storm was consistently clockwise and rising, all he had to do was aim a bit lower. He released. The next arrow was low and to the right, but was thrown vertically upward, also clattering to the ground.
The wizard in the middle of the wind shook her head. "The wind control spell is random in this casting; you can't rely on simply counteracting it."
The hunter nodded before switching arrows. His normal arrows were simple training tips, but this new arrow was weighted lead shot with a blunted point, intended for knocking the wind out of someone rather than penetrating. He drew again and fired. This time, the arrow still got blown off course, but only slightly, and Rigana winced as she reflexively shielded against the lead stunner flying past her head. 
"Dangerous but interesting. How heavy is that arrow?"
Vance shrugged. "About six pounds, maybe? Only heavy warbows like mine can hope to shoot it at any range." He lined up another shot and fired. This time, his aim was spot on, just to the right of the target, and Rigana stumbled backwards, her personal mage's shield taking the full direct hit of the stunner arrow.
Rigana waved him off. "Enough." She focused, drawing her spell out of the Wind Guardian, and the winds ceased. "Looks like we've found the upper limit of the protection these things provide."
The hunter frowned. "That wind protection is pretty difficult to overcome. Nobody out there carries lead stun arrows on a regular basis. They're a specific innovation of the Mercenary's Guild. All of the other arrows go wide."
"Well, hopefully no Wizard of the Association will end up being shot at by a mercenary." Rigana picked up one of the stun arrows and inspected it. "Would have hurt pretty badly to have been hit by this thing."

Mechanics & Inner Workings

The wind control spell in its generic form allows a magus to control wind intensity and direction. In the preparation of a Wind Guardian, a magus must specifically direct that wind travel around them intensely, in either a clockwise or counterclockwise pattern. The exact strength of the wind is dependent on the wizard's own skill; some wizards cannot produce useful Wind Guardians at all, while others can create localized tornados, proof against almost all attacks. 
The latent duration enhancement that Resonance Mineral provides ensures a reasonably long-lasting barrier, regardless of windspeed and strength. A Wind Guardian can expect to provide its barrier for nearly thirty minutes before petering out and requiring a magical recharge.

Manufacturing process

Wind Guardians are not manufactured, per se; they're simply lumps of Resonance Mineral , shaped in such a way as to project a spherical magical field of effect when infused. Spot infusion with a wind control spell generates the appropriate defensive wind barrier, but the spell must be repeatedly infused to maintain the effect.

History

Experiments with the Mage's Shield at the Wizard's Association of Etoile showed it was an unusually strenuous spell for most wizards. While it is proof against almost all physical or magical attacks, its limitation is that either a wizard could only maintain the shield for a vanishingly small amount of time, or it would only work in a given direction. These same limitations extend to the infusion of the spell in Resonance Mineral or examples of the Greatcoat of the Archmagus; no wizard could hope to maintain a permanent shield for any significant length of time.
Orthogonal thinking led to the proposal of an alternative - instead of a true shield spell that would stop everything, why not a directional wind spell, of sufficient strength to divert projectiles? Experiments led to a proof test where a number of archers and crossbowmen attempted to shoot a wizard channeling a wind control spell of such intensity as to resemble a localized tornado; the bolts and arrows were swept aside harmlessly. 
Wind Guardians are that same spell, infused in Resonance Mineral. Once a wizard casts a wind control spell into a lump of Resonance, a small windstorm appears around them, of sufficient intensity to stop all projectile attacks, though it will not protect against a melee attacker (say, a swordfighter), nor will it protect against large storms flinging very large pieces of debris.
These were researched in 725 in the hopes that they could be used to create a safe harbor at Port Raefel on Raefel Island for trade. This hope was dashed, as the storms of Raefel were simply too strong and overcame the much weaker winds created by Wind Guardians. They're now another product of the Association without an obvious market, though more than a few wizards have learned the precise wind control spell required to create a Wind Guardian from spare Resonance Mineral.

Significance

While an interesting development in the use of magic for defensive purposes, wind guardians are not strong enough to divert flywheel launches from a launcher turret, and they thus have limited military use. The Wizard's Association intends to instead position these as part of a security service; should someone come under attack, a wizard using a Wind Guardian could instantly create a wind barrier against arrow and bolt attack.

Item type

Magical

Creation Date

725

Rarity

Extremely rare

Weight

2lb

Dimensions

About the size of a rock in the hand