Go to Shadowfang Keep and obtain the Silverlaine Family Sword from Baron Silverlaine, 5 crates of Moonsteel Ingots, and 5 Deathless Sinew.
From your earliest days, your trainers always knew you would make your mark on the Horde. You have fought bravely and given our enemies reason to fear.
As a reward for your dedication, the warchief has commissioned his personal smith to forge a special weapon.
The cursed Shadowfang Keep in Silverpine Forest is the only place to get the materials you'll need. Travel there and find the lost Silverlaine family sword, a supply of moonsteel ingots, and sinew from the ghouls and geists infesting the keep.