Celtic Heroes

Hey guys,
I saw some people with a greater twinsoul necklace.
When i ask them about this they dont respond.
So my question is where can i find this necklace?
Thanx allot.
Sorry for my english

This item is a 'rare' drop in dustwither catacombs
I don't have the list of everybody who drops it, but I have received one from a 2-star withered fiend (located on the eastern cadaver room with dicarius)

I got two of them while I was camp/farming on lvl 29 darkbones