The Phurbas origin's started in Tibetan Culture. The Phurba is known as a magical dart to keep your foes at bay and also to ward off evil and dispel negative energy. The faces are Vajrakila or Vajrakilaya. Vajrakilaya, or Kila, means something sharp and something that pierces,like a dagger. A dagger that can pierce anything but can not be pieced by anything. The magic of the Magical Dagger,or Phurba comes from the effect that this material object has on the spiritual world. The art of Tantric magicians or lamas lies in their visionairy abilities to comprehend the spiritual energy of the object and willfullly focus it in a determined direction. Traditionally the tantric use of the Phurba included curing disease, exorcism, killing demons, meditation, and creating weather changes. I believe it may be applied to enhance the minds focused prayer on anything. The blade of the Phurba is used for the destruction of demonic powers and the top end is used by the tantricas for creating blessings.