In order to summon Lord Valthalak we're first going to need to gather the other two-thirds of the amulet. To do that we need to get a brazier and some special coals to burn in it.$B$BThere are three nobles of fire, Lord Incedius in Blackrock Depths, Pyroguard Emberseer in Blackrock Spire and The Duke of Cynders in Silithus, with what we need. Collect from each a piece of their remains, and then return to me with a Hallowed Brazier, which can be purchased from the Argent Dawn if you are honored by them.