The Theramore Elite Guard is the royal guard of Jaina Proudmoore. They were presumed to be her personal knights who had served her through the Third War. Their function was to protect the Lady. ( The Elite Guard was sent to )Northwatch by Chamberlain Kristoff, while the Lady was away, and engaged the Horde in a short skirmish that attempted to lay siege to the keep but was stopped by the timely arrival of Warchief Thrall. They are presumed to have resumed their duties as royal guards for Jaina.
They are, however, absent from World of Warcraft.
They could be the new name of the Kul Tiras Elite Corps seen in the Warcraft III campaign Cry of the Warsong. And the two knights accompanying Jaina in Where Wyverns Dare are presumed to be part of the Guard.