Gravewalker's Hand is a Unique Gloves in Diablo IV Season 15. It drops from Bartuc, Lord of Chaos.
Unique power
Your Essence Generation is increased by [30 - 40]%. Your Bone Skills deal 0.5%[x] increased damage for each point of Essence you have when Cast, up to [60 - 80]%[x].
Affixes
+1-20 Maximum Resource
Where it drops
Bartuc, Lord of Chaos (Lord of Hatred Lair Boss) per one guide
Random world drop / any Lair Boss (one guide: 'drops at any Difficulty Tier, increased drop rate per Torment tier'); 3.2.1: all Uniques drop from level 1 in any Difficulty; targetable via Horadric Cube reroll