The Tomb of Sargeras

The Tomb of Sargeras is an audio drama written by Robert Brooks, and narrated by Steven Pacey. It blends iconic music and sound effects from the series with prose. It features, Kil'jaeden and Khadgar. It is a part of the World of Warcraft: Legion literature. It was released in August 2016.

Descriptions
Gul'dan's efforts to corrupt the Iron Horde on Draenor have ended in failure. The Burning Legion is giving him one last chance to redeem himself by finding the Tomb of Sargeras… but he is already growing tired of the demons' tight leash.
 * The Tomb of Sargeras - Part One - The Fate of Another

Khadgar has pursued Gul'dan from Draenor to Azeroth, tracking the warlock all the way to the Broken Isles. There are enemies here, but it might be Khadgar's allies who give him the most trouble.
 * The Tomb of Sargeras - Part Two - Old Friends

The battle between Gul'dan and Khadgar rages within the Tomb of Sargeras. The fate of Azeroth hangs in the balance.
 * The Tomb of Sargeras - Part Three - The Tomb's Fury

Gul'dan has won. Khadgar has been defeated. But perhaps the Burning Legion has lost as well. The future of Azeroth—and the Legion's plans—hinges upon what Gul'dan chooses to do with his power.
 * The Tomb of Sargeras - Part Four - Standing Alone

Locations

 * Broken Isles
 * Broken Shore
 * Tomb of Sargeras