PRAAG @ 59, 19. Loot the paw from the source: Deadmaul, inside his cave. He doesn't drop it very frequently around 8%. Sell this to a merchant for unlock.
Note: This mobs respawn seems quite long for the 8% drop rate... will report back with time.
PRAAG. Kill Ursun Bears at the Ursun's Den (middle of E map border) to get a Deadmaul's Paw. Sell this to a merchant for unlock.