The second Wraithguard can be created after you gather three items: The 'Unique Dwemer Artifact', Kagrenac's journal and Kagrenac's planbook. The first item, the Unique Dwemer Artifact, is the unenchanted second wraithguard, and you can only get it by killing the demi-god Vivec. He is, however, an essential NPC for the game's main quest so you should only kill him after you have completed the main quest (or if you do not care to finish it at all). The item will be on his corpse. At this point you can take the 'dwemer' artifact (which looks like nothing more than a daedric gauntlet) to the last of the Dwemer, Yagrum Bagarn, who reside's in Tel Fyr in the corprusareum. He will ask you to retrieve two of Kagrenac's books. (note: Have the Unique Dwemer Artifact and the written plans to defeat Dagoth Ur with you, as Yagrum examines these items before he agrees to help you.) The first book, Kagrenac's journal, is held by the NPC Dagoth Endus. He is a rather polite fellow, and even offers you a valuable drink before you attempt to chop each other up. He can be found within the Ghostfence at Endusal (which is to the west of Odrosal, near the Ghostgate). Kill him, and Kagrenac's journal will be on his corpse. Two down, and one to go. The final item, Kagrenac's plans, can be taken from Dagoth Tureynul (who is located in Tureynulal, which is also inside the ghostfence and just northeast of Odrosal). This NPC is less polite than his brother, and will skip pleasantries and jump right to fighting you. That's alright, though; just kill him in whatever manner you please and pluck from his corpse the second of Kagrenac's books. Now that you have everything you will need, travel back to Yagrum in Tel Fyr. The Dwemer will ask you to wait a day while he studies the books, so sit tight (note: If you have a guarskin drum in your inventory, the corprus beasts in this area will not attack you). After 24 in-game hours have passed, Yagrum will warn you to fortify your health as much as possible before he 'harmonizes the wraithguard to your magicka signature'. In layman's terms: this gauntlet is going to bite you, and hard - it will instantly (and perminently) leech 200 hitpoints from your character. This only happens once, though, and after that you will have another wraithguard that is just as powerful as the first.

Type this in EXACTLY how it is shown. First press the ~ key.. then type.. player->additem "wraithguard" 1