Acherus: The Ebon Hold
Death Knight Leveling Guide (55-56)
1) Talk to The Lich King [A] and accept "In Service of the Lich King".
2) Turn it in to Instructor Razuvious [B] and accept "The Emblazoned Runeblade". Pick up a Battle-worn Sword and use it on a nearby Runeforge.
3) Turn it in and accept "Runeforging: Preparation For Battle". Go back to a Runeforge, then open your spellbook and use Runeforging to emblazon your Runed Soulblade. Your choice is either Rune of Razorice or Rune of Cinderglacier. Turn the quest in and accept "The Endless Hunger".
4) Unlock a soul prison in the center ring and kill the Unworthy Initiate. Turn it in and accept The Eye of Acherus.
5) Go back to The Lich King [A], turn the quest in, and accept "Death Comes From On High". Use a nearby Eye of Acherus Control Mechanism and analyze the four buildings. Use the Shroud ability to stealth then use Summon Ghouls to distract the guards before you siphon. Turn this quest in and accept "The Might Of The Scourge". Enter the transporter down the stairs.
6) Head in and turn the quest in to Highlord Darion Mograine [C]. Accept "Report To Scourge Commander Thalanor". Also, go to Lord Thorval to the NW and complete "The Power Of Blood, Frost and Unholy". Go back SE to turn in "Report To Scourge Commander Thalanor" and accept "The Scarlet Harvest". Use a nearby Scourge Gryphon to fly to Death's Breach.