Wraith is a Vanisher and a member of the Black Swan, and is part of the Collective. He disguises himself by only vanishing himself and leaving his cape visible, but does not show his appearance, making his voice eerily disembodied.
Book appearances Edit
In Book 4: Neverseen, Wraith welcomed the group to Alluveterre. He also worked with Della and Biana on their Vanishing abilities (which had significantly improved after some time). And in Book 5: Lodestar after the Rimeshire Sleepover and while informing Sophie, Fitz, Biana and Dex that Wylie was captured.
In Book 5: Lodestar, when Sophie, Fitz, Biana, and Dex discovered that somebody had put a listening device in "Sophie's" imparter, Wraith was the only member who Juline/Squall was able to reach. After telling them that, Juline left to see if Wraith had made contact with the rest of the collective. Wraith also tries to reassure Alden that what Alvar's done is not his fault.
In Book 7: Flashback, Wraith and Blur were backup. Wraith discovered someone to join the Black Swan. He also had a fight with Councillor Alina which was described as "especially bizarre" considering that Councillor Alina was yelling at a floating cloak.
There are many possibilities on who Wraith is, but he is probably a character briefly introduced or a character not known yet.