Remembrance of the Regal Ancestor Spirit, hewn into the Erdtree.
The power of its namesake can be unlocked by the Finger Reader. Alternatively, it can be used to gain a great bounty of runes.
Ancestral spirits exist as a phenomenon beyond the purview of the Erdtree. Life sprouts from death, as it does from birth. Such is the way of the living.
While Remembrances can be duplicated more than once through different Wandering Mausoleums, they can't be traded for a copy of an already obtained item in the same playthrough.