Unlike the Heroic Avatars that you’re already familiar with, Legendary Avatars provide 1% more Main Stat each, as well as 5 additional rapport attributes (Intellect, Bravery, Charm, or Kindness). 1% more main stat roughly equates to about 0.5% more Attack Power.
The only way to get them, besides buying them from other players if your region permits it, is to use a jar item in the cash shop to take Fabric and RNG it among a pool of Heroic Avatars.
Any non-free non-event costume can be dismantled into 7 Fabric, or 14 if it’s a suit that occupies the top and bottom. This amount is static and is not RNG.
Right click the jar and you’ll get this interface. You can choose which class you want to use the Fabric for from the scrolling menu beneath the jar, as well as the specific avatar slot you want to try to gamble on. On the right, you can see the pool of items the jar can create, as well as buttons to preview them. You can see the cost of Fabric below. All items will typically cost 14 Fabric to attempt to RNG a new costume. So, 2 dismantled costumes for a chance at a Legendary one.
Costumes that you acquire through this jar are bind-on-equip, meaning they can be sold.
On average, players observed that they obtained a Legendary avatar about 1 in 8 attempts, with varying probability surrounding it.
The cost to obtain a Legendary avatar set seems very severe, however given the amount of extra damage it provides is constant, it remains relevant forever even as you move through new sets of items. They are effectively a 2% global increase in damage over purple costumes.
One last note, once you have a Legendary avatar equipped, it’ll actually unlock a skin slot. This way, you can wear your favorite costume over it while maintaining the positive stats of the Legendary avatar. The skin slot is only available while a Legendary avatar is equipped (there’s not really another reason to have it).
As of writing this guide, there have been two series of Legendary avatars. When we move on from one series to the next, the old series can no longer be obtained from the cash shop, meaning the circulation of these avatars is limited by the existing ones players have.