The Void H only has Zebuxoruk in it and he only offers the first Neriak Partisan Quest, he is also involved in some Hails on various other quests in the Expansion.
Tasks go in - order, if an | exists it means you can do those in any order, but have to all be done to continue on to the end. If tasks aren't listed in a chain, they can be done at any time.
Progression Quest Chain: Overcoming the Cataclysm - Not of This World - Answering the Call - The Bixies of War | For the Sake of the Forsaken - The Missing Scroll - Fourth Gate Investigation - Cautious Recruitment
Mission Quest Chain: The Missing Scroll - Fourth Gate Investigation - Cautious Recruitment - Houses of Thex - Hate Rising
Mission Quest Chain: The Doomscale Horde - The Defense of Lendiniara | Xulous Prime - The Legacy of Bayle | Saving Jacyll | Houses of Thex - Hate Rising | The Fall of Lord Bayle | Burn Out - A Guide Beyond the Rift - The Journey Home