The Infernal Machine is a device in Diablo III used to open a portal analogous to the Über Tristram event in Diablo II. Once inside, the player can battle two Über versions of Act Uniques for an opportunity to collect organs to create a Hellfire Ring or (as of Patch 2.1) a Hellfire Amulet.
To craft the Infernal Machine, players will first need to collect all components from Unique monsters called Keywardens in each of the first four Acts on any Torment difficulty. The Keywardens can be found in the following areas:
- The Key of Destruction (Key of Bones on level 70) will drop from Odeg the Keywarden in Act I - Fields of Misery
- The Key of Hate (Key of Gluttony on level 70) will drop from Sokahr the Keywarden in Act II - Dahlgur Oasis
- The Key of Terror (Key of War on level 70) will drop from Xah'Rith the Keywarden in Act III - Stonefort
- The Blacksmithing Plans (and Key of Evil on level 70), as well as a small chance of any of the above components, can be dropped from Nekarat the Keywarden in Act IV, Silver Spire Level 1.
The DeviceAfter all the components (three for level 60, four for level 70) have been collected, they can be assembled in town at the Blacksmith. The Blacksmith will need to be level 10 (12 at 70) in order to learn the plans (sold by Squirt the Peddler), and requires 12,000 gold (100,000 on 70) to forge the device in his furnaces. Once assembled, the device will be account bound. It can only be activated in a cellar in New Tristram known as the Heretic's Abode. Activating the device will create a red portal which leads to a realm where a pair of Über Bosses must be defeated for a chance to drop one of three organs. Activating the device will also destroy it, so the player will need to collect the keys again and pay the 12,000 gold to construct another one. The Blacksmith, however, will not need a new set of plans.
Upon entering the portal, characters will be transported to one of three randomly selected Realms of Pure Evil, where a predetermined pair of bosses awaits: King Leoric and Maghda in the Royal Crypts, Ghom and Rakanoth in the Larder, or Siegebreaker and Zoltun Kulle in the Edge of the Abyss. On level 70, there is a fourth portal, where you will fight Shadow of Diablo in the Realm of Terror. You may only activate the device on Torment I difficulty or higher.
On level 60, each device opens a random portal, but if you activate three devices in one game, you are guaranteed to receive one portal of each type. On level 70, you must choose which type of the machine to craft, but it will always open a specific portal: Bones (Leoric + Maghda), Gluttony (Ghom + Rakanoth), War (Kulle + Siegebreaker) or Evil (Shadow of Diablo).
For successfully defeating a boss pair, players will be rewarded with extra items and gold. In addition, they will also have a chance to harvest the crafting ingredients from each of their fallen foes, which can be used to create the Hellfire Ring or the Hellfire Amulet. Crafting ingredients will drop the same for all party members. If one player gets an ingredient, all players do.
- The Writhing Spine (Leoric's Regret on level 70), which drops from King Leoric or Maghda.
- The Devil's Fang (Vial of Putridness on level 70), which drops from Ghom or Rakanoth.
- The Vengeful Eye (Idol of Terror on level 70), which drops from Siegebreaker or Zoltun Kulle.
- The Heart of Evil, level 70 only, which drops from Shadow of Diablo.
With the three (four for the level 70 variant) pieces mentioned above and 2,000,000 (100,000 for the console, 5,000,000 for the level 70 plans) gold, buy the plan(s) from Squirt the Peddler. A level 10 Jeweler can craft the basic Hellfire Ring for a fee of 50,000 gold, while a level 12 Jeweler can make the upgraded Hellfire Ring and Hellfire Amulet, for the same fee of 50,000 gold.