Recently, Diablo 3 added a new endgame feature that allowed players to face continually increasing challenges in their quest for better loot. The process to acquire the items needed to explore these rifts is not difficult, but there are a few requirements.
Step One: Bounties
The first thing you need is to run several bounties. In order to this, you need to start a game in Adventure mode (opens up after you have beaten the game with a character). The bounties are available in all five acts.
You pick a bounty by pulling up the map (M) and clicking on an exclamation mark on the map itself. Mousing over the exclamation mark will give you details about the bounty, which can include killing a specific named and several minions, completing a dungeon, completing an event, etc.
When you complete these bounties, you will frequently receive a Rift Keystone Fragment. This is required for the next step.
Step Two: Standard Nephalem Rift
Take a Rift Keystone Fragment (one per character, bound to account) and click on the Nephalem Obelisk. This will open a portal to a Standard Nephalem Rift. Proceed through the rift until you encounter the Boss. This will likely take you through several zones by going “down” and each zone can be very different. Within the Standard Nephalem Rift you can expect the following features:
Standard Nephalem Rifts are not timed
Loot can drop off of any mobs, especially Champions and Elites.
Treasure Goblins do exist in Standard Nephalem Rifts.
Shrines and upgraded versions called Pylons exist.
The Boss will spawn after enough minions have been defeated.
The Boss may drop a Keystone of Trials (required for Step Three).
The Keystone of Trials appears to only drop for level 70 characters.
The Keystone of Trials may drop at lower difficulties, but I have only seen them on Torment.
Step Three: Keystone of Trials
After you have acquired a Keystone of Trials, it is time to test your abilities. Access the Nephalem Obelisk and use your Keystone of Trials (each party member needs one). This will put you in a timed challenge with progressive waves of monsters until your ability is determined. You will then be awarded a Greater Rift Keystone Rank X, X is a number referring to how difficult the Rift will be.
Step Four: Greater Nephalem Rift
Using the Nephalem Obelisk, once again, you now have access to the Greater Nephalem Rifts. Use your Greater Rift Keystone to start the rift. Each character must have a stone of equal or greater value to join you. Proceed through the rift quickly, you only have 15 minutes to spawn and kill the boss (to receive a more powerful keystone).
Things to expect in a Greater Nephalem Rift:
Skills cannot be changed within a Greater Nephalem Rift.
Champions and Elites drop orbs that increase the kill meter.
Only the Boss drops equipment, frequently including legendary items.
Treasure Goblins do not exist in Greater Nephalem Rifts.
Some Pylons do exist, but they are very rare.
If you complete the Greater Nephalem Rift within 15 minutes, you may upgrade your keystone.
Upon completion, within or after time, you can attempt to upgrade 3 legendary gems.
After completing a Greater Nephalem Rift after time has expired or you chose not to upgrade your keystone, you will need to go back and repeat steps to acquire another Greater Rift Keystone.
Have fun with the rifts! If you have any comments or observations different from my own, comment below and let me know.