This artifact is a one handed mace made from the backbone and skull of a mighty (although small) demon who was famous for his fondness of collecting the souls of the undead.

Powers:
Unbreakable
Immune to Paralyzing and Stunning attacks
Immune to lvl- and abilitydrains
Immune to Mind- and Soulaffecting attacks
Immune to Fear
Immune to Negative Energy attacks

Acts as Mace of Disruption
+5 Mace vs Undeads
+5 AC vs undeads
+5 saves vs undeads
+50% MR vs undeads
Dmg: 10d6 vs undeads

Reduces the MR of undeads by 50% (does not cut their MR in half, but lowers it by 50%)
Bypasses the damage reduction of Undeads