#crystal cave

Dark Souls location series:Crystal Cave

“Ah, the secret of Seath’s immortality?
If you have fought him, and were imprisoned, you must know that Seath is a true Undead, different from ourselves.
His wounds close promptly, and no mortal blow affects him, granting true insulation from death.
It is an effect of the Primordial Crystal, a sacred treasure pillaged by Seath when he turned upon the ancient dragons.
So, only by destroying the Primordial Crystal can you so much as scratch his hide.
And it so happens, the Primordial Crystal is in the inner garden of these very archives, the Crystal Forest.”