Diablo 3 : Realms of terror ( Uber Bosses)

What you'll need

Key holder

1. Key of destruction found in act one fields of misery.
2. Key of hate found in act two dalhgur oasis.
3. Key of terror found in act three stonefort.
4. Infernal machine blacksmithing plans found in act four silver spire.

All four items are required to make the infernal machine which opens the uber portals.

Important : Before you kill each key holder or purple monster that drops the items be 100% sure you are at five nephalem stacks from killing elites and opening resplendant chests, or doing quest events.
If you are not at five nephalem stacks at the time the monster is killed there is a zero percent chance of the required item(s) dropping.

I got all the keys and plans what now?

Blacksmithing plans

Next step you want to teach the blacksmithing plans to the blacksmith.
Bring all three keys and have a substantial amount of gold, I believe 20k is the price.
Make the infernal machine.
Be sure you are in act one and find a wooden door just above where deckard Cain usually chills.
Smash the door and enter the house.

You will find an odd looking room with a satanic summoning type of setup, romantic candles etc.

Use your infernal machine and a red portal should open up. It should open only ONE boss instance which can be a combination of various act bosses and mini bosses. Once completed each portal should drop a legendary coloured "organ." Again three portals, three different bosses , and three different organs are required.

For best results try to collect three infernal machines or gather some buddies who have them as well.
Once you complete one red portal use an infernal machine again and it will open up the next corresponding instance.

Once all three organs are farmed ( Devils Fang, Spine, and Eye) bring all of them to the gem combiner and under the category "rings," you can select the best suited stats to your character and create your hellfire ring.
Again a small fee of 50k is required to make the ring.