The amulet of blood fury is an amulet of fury temporarily enhanced with a blood shard, granting a passive chance for life leech on melee attacks. When dealing melee damage, the amulet grants a passive 20% chance to heal 30% of the damage dealt on any hit. On average, players will heal for roughly 6% of the melee damage they deal. This can trigger independently from Guthan the Infested's equipment ability, and could potentially happen at the same time.
Once created, the amulet has 10,000 charges. Additional blood shards can be used to charge the amulet up to a maximum of 30,000 charges. A charge is depleted for every successful melee hit regardless of whether the amulet's effect triggers. For weapons that hit multiple times per attack (such as scythe of vitur), it may consume multiple charges per swing. When it runs out of charges, the blood shard breaks, leaving the player with only the amulet of fury.
Depending on the opponent's Defence, with a four tick weapon (such as the abyssal whip or Ghrazi rapier), one shard will last for approximately seven hours of sustained combat before depleting. When using the Scythe of vitur, one shard will last approximately 2 hours and 45 minutes. The total health that a fully charged amulet will heal is approximately the player's maximum hit multiplied by 300: for example, with a setup with a maximum hit of 50, the amulet will heal 15,000 hit points on average before breaking.
When killed by another player and the amulet of blood fury is not one of the items protected on death, the amulet is converted to a normal amulet of fury; the blood shard and any remaining charges are lost.