The Athame is a ceremonial dagger introduced by the RedPower mod that is especially suited for fighting Endermen.
The sole purpose of the Athame is to provide an effective means of fighting Endermen. While it is does only mundane (half heart) damage to players and regular mobs, this blade simply rips through Endermen. It takes only two strikes to kill an Enderman, making the Athame very useful for gathering Ender Pearls or fighting off armies of Endermen in the End.
The Athame is created by combining a Silver ingot with a stick in the crafting table: