Enchantment

"My son, if you learn nothing from me, know that you must never trust an enchanter. I paid one my life's savings to make for you a suit of armour that would keep you safe. Instead we now have jarvis here, A SUIT OF GOD'S DAMN ARMOUR THAT CAN ONLY PASS US BUTTER.
Master, would you like some more butter?
NO JARVIS, *sigh* no thank you"

Enchanting is an ancient magical craft in Calradia, and has been at the heart of the creation of many items of legendary strength and influence. 
enchanting is conducted by a wizard, specifically trained in this art over all others, and an enchanter may not even be able to cast other magic, as they have focused entirely on this very complex process. The wizard enchants an item by channeling the atmospheric winds of magic down to the earth, and literally traps some of the wind into the metal, by having it run through specifically crafted runes and engravings in the metal. Suffice to say, the quality of the item being enchanted must be extremely high, as the metal itself has to be able to contain the power being thrust into it. Once the process is complete though, an item has been created that has a magical property forever, unless destroyed. Such items are rarely destroyed though, not because of their astronomic power and cost (but that is absolutely a factor),  but because the destruction of the item releases the magical power trapped within it often killing those in close proximity. The stronger the enchantment, the more destruction occurs when it is released, with the most powerful of items being known to be able to wipe out entire towns or even cities (though this is rare, as the difficulty to destroy such an item increases exponentially with it's power).

Access & Availability

Enchanters can often be found within all major cities, and are willing to sell their services for a hefty price. Enchanting can also take anywhere from a couple days to a couple years, and is highly influenced by the winds in the region it is being produced. In winds of magic nexus locations, like Illyria City, the resulting items are of much higher power, but also much higher complexity, so that the enchanter does not kill themselves or others by mishandling the winds they are pulling down from the heavens.
The costs of enchantment are not insubstantial, as you must pay both for the time of a master enchanter, as well as the magic ingredients and items that they require to do their work for as long as you require them. Thus, enchanting is often a service reserved for the very wealthy, or states looking to produce implements of war.

Complexity

Enchanting an item can be a lengthy process, and sometimes unpredictable due to it's reliance on the winds of magic to power it. Some lesser enchanters aren't even able to choose which enchantment will result, as they are not skilled enough with manipulating the winds of magic to produce a specific result.