Echo of Kwatli is a Unique Amulet in Diablo IV Season 15 for Spiritborn. It comes from Astaroth (Escalating Nightmare Dungeon); Horadric Cube: Upgrade Common Amulet to Unique.
Unique power
You deal [53 - 67]%[x] increased damage to Vulnerable enemies. After making an enemy Vulnerable, your next direct damage dealt to them: Heals you for 5% of your Maximum Life, Generates 10 Vigor, Removes the Vulnerable effect.