Boss Item's & Upgrade Level's.
Abyssal Sword Normal/Rare/Legendary 675 Normal +2 725
Dark Soul 725 +2 is 775
Satan's Ace Normal/Rare/Legendary 775
Thanato's Wings Normal/Rare/Legendary 775 Normal +2 825
Ring Of Existance 900
Legion Sword/Armor Normal/Rare/Legendary 800

There are many item types in the game. Below are all the item types in the game:

Item Types 1/2
Common (Normal, weak items, these are the only items that DO NOT SAVE)
Quest (Items that are obtained through quest means. They are generally strong.)
Boss (Items that are obtained off Bosses. They are generally the same strength as some Quest items.)
Chaotic (Items that are obtained off normal creeps in the Chaotic World. They are generally extremely powerful)
Chaotic Set (Items that are forged from all the items in their set. Not only does it make an item that has the strength of 3 - 5 items, it also increases the power of the effects by 50%. Chaotic Sets are generally very helpful and wield immense power.)
Chaotic Boss (Items obtained off Chaotic Bosses. They are generally earth - shaking in strength and drop 90% of the time from most bosses.)
Rare Chaotic Boss (Items that have only a 9% chance to drop from Chaotic Bosses. They possess 2x the power of the original boss item.)
Legendary Chaotic Boss (Items that have only a 1% chance to drop from Chaotic Bosses. They possess 3.25x the power of the original boss item.)
Infinity (Items that are obtained off of the boss Infinity in the Chaotic World. (Infinity is not implemented yet.) Infinity items generally have such power that they can obliterate enemies with ease. They have a 50% to drop from Infinity.)
Rare Infinity (Items that are obtained off of the boss Infinity in the Chaotic World. (Infinity is not implemented yet.) Infinity items generally have such power that they can obliterate enemies with ease. They have a 5% chance to drop and possess 2x the power of normal Infinity items.)

Item Types 2/2
Legendary Infinity (Items that are obtained off of the boss Infinity in the Chaotic World. (Infinity is not implemented yet.) Infinity items generally have such power that they can obliterate enemies with ease. They have a 0.5% chance to drop and possess 3.25x the power of normal Infinity items.)
Chaos (Items obtained off the ultimate boss, Chaos. Players who have fought together in groups of 8 with the most powerful items (Legendary Infinity +5 Items) and auctually brought down this creature, will have these types of items. Chaos items are called the "Alpha" and the "Omega" because they have such immense power that they can destroy and recreate everything freely. These items have a 30% chance to drop.)
Rare Chaos (Items obtained off the ultimate boss, Chaos. These items have a 3% chance to drop and possess 2x the power of Chaos items.)
Legendary Chaos (Items obtained off the ultimate boss, Chaos. These items have a 0.3% chance to drop and possess 3.25x the power of Chaos items.)
Upgraded (Items that can be upgraded up to +5, increasing their power by 300%. All items except Common and Chaotic can be upgraded. However, Rare and Legendary are not upgraded through the normal upgrader. They are upgraded via the Rare Item Upgrader and the Legendary Item Upgrader. Rare items upgrade cost is higher than normal items, and Legendary upgrade cost is much higher than normal item upgrade cost.)