World of Warcraft: Shadow Wing, book 2 : Nexus Point

In Warcraft: The Sunwell Trilogy, a good-natured but brash blue dragon, Tyrygosa, and the human Jorad Mace, a paladin struggling to reconnect with the Light, emerged victorious in the Ghostlands after ending the undead Scourge's quest to obtain the Sunwell's potent energies. Yet Tyri and Jorad's epic adventure was far from over! Both were drawn into the Dark Portal and transported to the shattered world of Outland, where they encountered a group of enigmatic creatures unlike any they have ever seen: the incorporeal nether dragons.
Meanwhile, Ragnok Bloodreaver, one of the original death knights, has enslaved a host of nether dragons and marches his fel orc army to the Dark Portal... where his brutal takeover of Outland will begin. If Outland falls, will Azeroth be far behind ? Seeking redemption, Jorad rallies The Broken and warns the Alliance of Ragnok's pending attack, all while trying to prevent Tyri from falling under Ragnok's control...

Titre original : World of Warcraft: Shadow Wing, book 2 : Nexus Point (2011)