Blood Furnace

The Blood Furnace is the second wing of the Hellfire Citadel. The instance takes place above Hellfire Ramparts, inside of the tower that overlooks the ramparts themselves. The entrance is on the Alliance (Southern) side of the Citadel, up a ramp that starts at map coordinates. You come to find out, in the course of the instance, that it is Magtheridon that is entrapped by the fel orcs' sorcery, and they're using his blood to manufacture a new Fel Horde, infused with his demonic energy. The guiding force in this plan is Illidan, who is now the supreme ruler of Outland, after his usurping of Magtheridon.

The instance is around one and a half times to twice as long as Hellfire Ramparts, and has the same number of bosses.

For years, this gargantuan fortress was thought to be abandoned, but it's now inhabited by marauding bands of red, furious fel orcs. The presence of this new, savage breed presents something of a mystery, though what is far more disconcerting is that the numbers of these fel orcs seem to be... growing.

At the heart of Outland's barren Hellfire Peninsula stand Hellfire Citadel, a nearly impenetrable bastion that served as the Horde's base of operations throughout the First and Second Wars.

• Felguards
• Felhunters
• Fel orcs
• Observer (one, Broggok)
• Imps
• Mag'har orc
• Mo'arg (one, the Maker)
• Succubi

• Heart of Rage (quest)
• Make Them Bleed
• Mind the Gap
• The Breaker
• WANTED: Keli'dan's Feathered Stave

• Heart of Rage (BC Classic)
• The Blood is Life

Killing monsters in this instance on normal difficulty grants Thrallmar or Honor Hold reputation. Reputation stops at Honored, bosses included. Heroic goes to Exalted, though. A full Heroic run will earn roughly 2500 rep.

• The Blood Furnace (achievement)
• Heroic: The Blood Furnace
• Heroic: The Blood Furnace Guild Run

• The novel Beyond the Dark Portal stated that the throne of the Old Horde (and then of the Horde of Draenor) was situated in Hellfire Citadel's back, in a taller tower with a peaked roof. Architecturally, this would mean the tower of the Blood Furnace, but no such throne room can be found in-game.