Who are the wind wolves in Codex Alera?
An interesting question.
The main use of this term in recent literature is found in Jim Butcher's fantasy series, The Codex Alera, which focuses on a civilization based on Roman culture that somehow got transported to a different world. In this world, people can essentially do magic though teaming up with (or imposing their will on) creatures known as furies. These creatures are like elementals of various natural categories: wood, earth, fire, etc.
The Wind Wolves are a set of mercenaries employed by a major contender for leadership of Alera, who you might consider a traitor. They are led by Aldrick ex Gladius, who is the second or third best swordsman in existence. They show up in several of the books in the series, flying through the air (though the use of "wind furies") to engage in titanic battles against humans and non-humans (namely the "Vord"). They play a major role in Furies of Calderon, and a more modest role in Academ's Fury, Cursor's Fury, and First Lord's Fury.