Iblis, Blade of the Fallen Seraph



Iblis, Blade of the Fallen Seraph is a fast one-handed sword with a blue glow, similar to that of the weapon damage enchant.

Source
Iblis, Blade of the Fallen Seraph drops off Instructor Razuvious, the first boss in the Deathknight Wing in Naxxramas in Eastern Plaguelands.