This quest is not available in game.
Speak to Maurin Bonesplitter in Desolace.
The Burning Blade have many agendas, but know that they are evil to their core, their spirits corrupted, and their destruction is the only way to thwart their objectives.
Keldran sent Maurin with me because of his knowledge of the Blade and their warlock ways.
He has control of our plots against the Blade while I deal with the other demonic threats here in Desolace.
Speak to him, and he will guide you in his designs.