No one knows who forged it.  It was used to slay the Orc Lord, Krail Othgot.  The blade was then put into the hands of Mo'thiil Greystone, one of the eldest Drow.

Elorn Greystone, 2nd Son of the House of Mo'thiil currently bears this dagger. Glandiiar Kyo'Lith was the original owner of this weapon before it was passed to the House of Mo'thiil.  There it was stolen by the 2nd Son of the Mo'thiil House, Elorn Greystone.
 
 

Abilities
The blade, when inserted into flesh, leaves a shard that slowly poisons the victim.  It first causes parallisis, then slowly kills the victim.

The weapon in almost unbreakable.  It is said that the only way to get rid of it is to cast it into The Great Pit in Mordor.