Its shape is reminiscent of the Crucificator, except that it is a dark violet color. It fires skull-like cursed balls at the enemies that chase them down similarly to Demon Disks. The Defiler balls, once fired, will explode once it hits anything, actual target or not.
When you simply shoot somewhere you will see that the bullet travels very fast and become quite slow when the bullets track the enemies.
Were it not for it being a special weapon, it's kills actually fall under shotgun kills earning one the Mess Maker achievement in Multiplayer.
For its price, the poor man's Hand of Kisin, the Defiler actually gives out more stun than the Hand of Kisin, and were it not for its slower fire rate and ammo count wanting, it could give the Hand of Kisin a run for the money.
In Single Player it fires faster than in Multiplayer.