Wraithverge

The Wraithverge is a weapon from Hexen. Parias, the Cleric, uses this weapon. It is a staff (verge) whose visible part is a large, ornate crucifix with a large ruby on the end. Like the Quietus and Bloodscourge, the Wraithverge needs to be assembled from different segments found throughout the game.

The Wraithverge is the most destructive weapon in the game. When fired, it shoots a sphere of spiritual energy which splits into four ghosts (wraiths) that rend and tear at enemies that get in their way. The ghosts can, however, be turned against the player if they fire the Wraithverge at any monster that is in protect mode (The Heresiarch's reflective barrier, the mage's Icon of the Defender, and Centaur/Slaughtaur in shield stance before the ghosts split from the original projectile) or if they are repelled with a Disc of Repulsion. The Wraithverge is also the most mana-consuming weapon in the game, requiring 18 of each kind of mana.

Source: Doom Wiki