J.M. Hunter wrote:So yea...what can you tell me about him?
If you're talking about me, Strict's post is a good place to start.

If you're talking about the fictional character, here's a bit of info that I've mentioned before:
In Teen Titans (first series) #45, Mal Duncan was given Gabriel's Horn from the angel Gabriel.
http://www.coverbrowser.com/search?q=Teen+Titans+45It was supposed to make him "the equal of his opponent", but in practice, it worked sort of like Scarlet Witch's powers did, causing any number of effects. This included teleporting other Titans to Mal, blowing back villains, doing the ol' "Pied Piper" routine with the Fiddler's collection of vermin, etc.
And a bit of newer info:
Mal said that he was going to destroy the Horn in Secret Origins Annual #3, after the villain Gargoyle used it to attack the Titans. Whether he did or not, Cyborg gave him a virtual Horn to use in JLA/Titans #2.