Weapon and Item Caliber

Weapons and Items all have different types of uniqueness and durability to them which makes it hard to determine how powerful they are from each other. For this reason, each weapon is brought to a crafter with a unique eye for spotting the subtle differences between weapons that make them better than others. These weapons are then put into different categories called CALIBERS.
There are 5 different CALIBERS of weapons and items that have been categorized by masters of their craft, but just because the CALIBER of a weapon is high doesn't mean that an inexperienced person could defeat someone who is very skilled at using that weapon. It also doesn't mean that the person will match the weapon that they are using. Matching a person to a weapon is key, simply because some weapons are uniquely made for the people that use them and therefore while anyone can wield a weapon or an item they may not be able to use the full capacity of the weapon.
The lowest CALIBER is that of BLANK CALIBER: This is for unregistered and unrecognized weapons. Most weapons that are manufactured in machines such as guns or preprocessed swords and other weapons. Most cursed objects are in this level, mainly because nobody was to touch an accursed item and risk the curse coming upon them.
The lowest ranked CALIBER is THIRD CALIBER: This categorizes weapons and items that are properly made with care and attention. This category usually consist of weapons made by students of the craft for their graduation ceremony. These weapons are usually more durable than most. Even being able to withstand the pressure of being 13 miles underwater. Items under this category aren't rare but they are not common either as there are a good variety of people who use them within the world. 
The second lowest ranked CALIBER is SECOND CALIBER: This category is used for items that are thought to be 90% to perfection. It is made by masters of the craft in their prime and will result in ferociously strong items; uniquely made for their owner or style of craft. Items with this rank are noted for being able to strike down boats and planes. The weapons in this CALIBER are thought to be elegant, beautiful, and ruthless. The items in this CALIBER, are thought to be unique and distinctive.
The second highest ranked CALIBER is FIRST CALIBER: This category is created by masters of the craft after their skill had been refined for years, and are usually their last few weapons they make. War hammers, swords, scythes, armor, mirrors (as in things such as the 4 Seasonal Demon Mirrors) it doesn't matter. These items are known as kingdom slayers as multiple stories about these weapons usually involve a person taking out entire cities, companies, and kingdoms.
The highest ranked CALIBER is ZERO CALIBER: These items are known as either Earth-Shakers or God Killers. These items are made by masters who have an eye for perfection. There are many myths and stories about these types of items, but one of the best is known as the "TALE OF MANDA", which is about a man who in an act of revenge about a kingdom who wronged him, he cut the entire city in two. The strike was so powerful, it hit the core of the planet and resulted in the first 11.0 earthquake., and split the kingdom from the mainland. The second half is now known as the FOREST OF TEST.