Items and armaments in YGGDRASIL were classified according to their data size. The greater the data, the higher the grade of the Item.
Starting from the bottom, the classes were:
Low
Medium
High
Rare (changed from Top)
Legacy
Relic
Legendary
Divine
ARTIFACT CLASS ITEMS
Artifacts are not related to specific ranks. It just means they are items with fixed data and stats created by the game developers. Therefore, artifacts with low rank to high rank powers can exist. Dropped artifacts cannot have its original name be changed or customized by players unlike most items in the game. Nonetheless, artifacts are regarded to be the highest class of magic items out there excluding World Items.
GUILD WEAPONS
YGGDRASIL's weapons — Guild Weapons and a few others aside — possessed a data capacity that was determined by the value of the materials used in their construction and the skill of their maker. This data capacity limited the number of data crystals which could be added to it. Thus, rarer metals are allowed for the creation of a correspondingly more powerful guild weapon.
WORLD CHAMPION ITEMS
The World Champion was a special class granted only to the victor of the official martial tournament. Only a few had managed to obtain the World Champion class of which there were only nine in YGGDRASIL. As for the prize, the champion was given one piece of special equipment by the administrator. The power of this prized equipment surpassed Divine Class items, rivaling even Guild weapons. Of course, since it was a reward for the winner of the tournament, only the World Champion could equip it.
WORLD ITEMS
There were only two hundred of these items in YGGDRASIL. Even Guild weapons and Divine-class weapons couldn't match them. World Items are the most powerful items admired and feared by players in the game. Given their rule-bending powers, in addition to the slim chance of finding them, a player who is lucky enough to come into possession of even just one of the World Items could easily shake the game's power balance. Basically, they are the "Wild card" or the "Joker card" of YGGDRASIL.