Many years ago, Ser Alvard had a sword made for him in the Blackmarsh. He asked that it be shipped to Amaranthine hidden in a crate of ordinary goods, but the crate never arrived. Ser Alvard is likely dead by now, but the blade might remain. The sword may also be dropped randomly after fighting the Avvar Crypt Lord beneath Vigil's Keep in the quest The Wraith's Vengeance.
The sword is found in the crates at the docks behind Baroness's mansion in the Blackmarsh.