User blog comment:Dragon´s Blade/World Coexistence Alliance/@comment-25005224-20140727115103/@comment-17807986-20140727174234

Morgul blades, also known as "Morgul-knives", were magical and poisonous daggers that were used by Ringwraiths in Middle-earth during the Third Age. After it tastes flesh, the dagger breaks, leaving the shard of the blade in its victim. The remaining blade soon turns to dust, and the shard works its way through the body to the heart. If the shard of the blade stays in the victim for too long the victim becomes a wraith.