We can't find any source for this item (quests reward, drop, etc). It's highly probable this item is not obtainable right now.
As others have reported, I upgraded a 599 version of this to 600 using 124 Umbral Shards and it did NOT upgrade to legendary. SMH...
Ok, if you drop it at 600 you get one out of 11 possible perks.
I upgraded a 599 to 600 and did not get a 3rd perk..
did anyone tried upgrading this ring to see if the ring turns into legendary?
i looted it 600gs legendary from Laz with infected Leeching sacred perk
Only Named items with "no other perk bucket" avaible will turn Legendary once upgrading with Umbral.
Since this ring has different perks available, it will not turn.