General Questions
What is it?
Those who played Diablo II might remember the Horadric Cube, a unique device which allowed you to combine items. Useful as it was, it was easily surpassed in power by the item from which it originated, Kanai’s Cube. In Patch 2.3.0, players will be able to discover this powerful ancient relic and utilize its incredible potential, including the ability to break down Legendary items and equip their special effects as passive skills (which are separate from your other passive skills), convert crafting materials from one type to another, and so much more.
How does it work?
The primary function of the cube is to serve as a collection system to allow you to accumulate powers from items and then assign the powers you want to use. This has a lot of benefits one of which is hopefully to help free up some of that stash space that players, like me, are using to save cool items "just in case". Now instead of keeping 1 of every cool item in my stash you can simply extract it's power for later use.
Anytime you extract a power from an item it is added to your collection of powers. You can enabled any power you have ever extracted, within each specific game type.
How many passives do you get?
One weapon passive, one armor passive, and one jewelry passive.
**Is Armor ARMOR, or ALL armors (bracers/gloves/etc)?
The armor slot for Kanai's Cube currently encompasses every slot except weapons and jewelry. So, for example, the cube could give you the Legendary power from Lut Socks, or Leoric's Crown, but not both.
Do the Cube passives replace normal passives?
Stopping by to say that powers assigned with the cube do not compete with normal passives.
Can you get cross-class passives (e.g. Flying Dragon on a Barbarian)?
You can only assign powers that you would normally be able to use so no Calamity on Barbs or Flying Dragon on Demon Hunters.
Are offhands (s, Mojos, Quivers, Crusader Shields) considered weapons or armor?
Anything that goes in your main or offhand is part of the weapon category for the purposes of the cube.
Can you stack two immunities from amulets?
If you want to wear an immunity neck and infuse yourself with a second immunity you can absolutely do that.
Can you double dip passives (i.e. wear a Furnace and use the Furnace cube passive)?
No double dipping, you can only have one instance of a power active.
Think of it this way: Equipping a power from a Legendary power via Kanai's Cube is just like equipping the item itself, only it does not take up an equipment slot.
How are legendary powers stored on your account?
Powers extracted via the cube are accessible the same way that paragon levels are. They are account wide per game type, Normal, Hardcore, Seasonal Normal, Seasonal Hardcore.
How are stat ranges in legendary powers dealt with?
Powers that are extracted into the cube are extracted at their maximum power.
Is it Season only?
...it is not a season only feature.
Where did this idea come from?
It's been in the works for quite some time. As with many features, it's a combination of player feedback and internal design.
Specific Items
Can you get an additional normal passive by extracting a Hellfire Amulet?
Also the Hellfire Amulet passives cannot be extracted via the cube.
How does the Hellskull shield work for a Demon Hunter not using a bow?
Hellskull increases damage while wielding a 2h weapon. That power can be used without requiring a shield to be equipped. If you want to trigger an on block effect from a power you will need a way to block or it won't be able to trigger.
How does the extracted legendary power account for Leoric's Crown and the Broken Crown?
In both of these cases it will give you the benefit based on whatever gem you have socketed into your helm.
Can you extract Ancestor's Grace (extra life)?
Ancestors Grace can't be extracted into the cube...