Kanai's Cube — The Complete Guide

Kanai's Cube is the single most powerful crafting tool in Diablo 3 and, since patch 2.3, the backbone of nearly every build. With it you extract legendary powers, reforge items, convert set pieces, augment Ancients and transmute reagents. Anyone serious about pushing Greater Rifts (GRs) cannot do without it — the Cube decides how many legendary effects your hero can run at once.

This guide walks you through unlocking the Cube step by step, every recipe with its exact reagents, which powers to cube per slot, and the mistakes beginners make over and over again.

What Is Kanai's Cube?

Kanai's Cube is an artifact recovered from the Ruins of Sescheron that once belonged to the barbarian chieftain Kanai. It is the precursor to the legendary Horadric Cube from Diablo 2 and, in Blizzard's words, holds "immeasurable transmutation power."

Functionally it replaces the old crafting station and enables five fundamentally important things:

• Extracting legendary powers from items so you can use them passively — without having to wear the item.
• Reforging (rerolling every affix) and upgrading items.
• Converting set pieces and crafting materials.
• Gambling rare items up into Legendaries.
• Augmenting Ancient items with enormous stats (Caldesann's Despair).

[info] The most important effect is the power collection: every power you extract once is stored permanently in your catalogue. Even if you destroy the source item, the power stays available forever and can be (re-)cubed at any time.

Why the Cube Is So Powerful

Before the Cube, every hero was limited to 13 equipment slots. The Cube effectively grants three extra legendary effects on top — a flat build upgrade that virtually every class is forced to use. This stacking of multipliers is exactly why modern D3 builds reach such high GR tiers.

Unlocking the Cube

The Cube sits in Act III, in the zone The Ruins of Sescheron, which is only accessible in Adventure Mode.

• First unlock Adventure Mode (finish the story campaign once, or have a friend host it).
• Open the Act III map and travel by waypoint to "The Ruins of Sescheron."
• Make your way through the frozen zone to the Elder Sanctum — follow the quest marker.
• In the Elder Sanctum the Cube rests on a pedestal, guarded by Kanai's spirit. Click it and pick it up.

[info] You only need to clear Sescheron once per account and game mode. After that the Cube lives permanently in your inventory across every hero. Season and Non-Season are tracked separately: in each new Season you must retrieve it again.

[tip] If you start a new Season from level 1, grab the Cube as early as possible — Sescheron is accessible from level 1. Extracting a single defensive power (e.g. Aquila Cuirass) makes the entire leveling process noticeably safer.

Opening the Cube

Once picked up, you can open the Cube anywhere via the icon at the bottom left of the screen — no trip to town required. You can also bind a hotkey for it in Options, which saves a lot of time when cubing frequently.

The Three Cube Slots

Extracted powers are sorted into three categories. You may have one power equipped per category at a time — so three powers total:

• Weapon — e.g. The Furnace, In-geom, Bul-Kathos's Blades.
• Armor — e.g. Aquila Cuirass, Illusory Boots, Nemesis Bracers.
• Jewelry (rings/amulet) — e.g. Convention of Elements (CoE), Unity, Halo of Karini.

[warning] Only one power is active per slot. Cube a new power into the same category and it replaces the old one. The Altar of Rites (a Season mechanic) can later unlock up to five cubed powers — but by default you are strictly limited to three.

Wear It or Cube It?

The central optimization question: some items you want on your body because you also need their affixes (Strength, crit damage, cooldown, etc.). Others give the identical effect when cubed and free up an equipment slot you can then fill with better stats. This trade-off is the very heart of the Diablo 3 endgame.

Rule of thumb: cubing a power is worth it when you need the effect but the item itself rolls poor stats — or when you need the slot more urgently for another item.

The Key Recipes

Every recipe is selected from the Cube menu; each requires a source item plus a material combination.

Extract Legendary Power (Law of Kulle)

Turns a legendary/set item into its raw power. The item is destroyed and the power lands permanently in your catalogue.

• Reagents: 1 item + crafting materials (Reusable Parts, Arcane Dust, Veiled Crystal) + Death's Breath.
• Cost: rises with progress; early on roughly 5 Death's Breath, far more later.

[tip] Only extract identified items, and always use the highest roll you can find — for percentage-based powers (e.g. damage multipliers) the source item's rolled value carries over.

Reforge Legendary (Skill of Nilfur)

Rerolls every affix on a legendary/set item — perfect for chasing a flawless Ancient piece. Each reforge also has a chance to produce an Ancient or even Primal Ancient version.

• Reagents: 50× Death's Breath + 50× each standard material + 1× Forgotten Soul.

[warning] Reforging is a gamble and extremely material-hungry. Only reroll items you truly want to perfect (BiS candidates), not every drop.

Convert Set Item (Skill of Akkhan)

Converts a set piece into another random piece of the same set — ideal when you're missing exactly one slot.

• Reagents: Khanduran Rune, Caldeum Nightshade, Arreat War Tapestry, Corrupted Angel Flesh (the act-specific bounty materials) + Death's Breath.

Upgrade Rare to Legendary (Hope of Cain — the "gamble")

Upgrades a rare (yellow) item into a random Legendary of the same item type. The most efficient way to fish for a specific Legendary.

• Reagents: 50× Death's Breath + 25× Reusable Parts + 25× Arcane Dust + 25× Veiled Crystal per attempt.

[tip] Choose the rare item type with the fewest possible Legendaries (e.g. a specific weapon type like a Flail) to maximize the odds of hitting your target item.

Convert Crafting Materials (Pages of …)

Converts 100 lower-tier materials into the next tier up — and back down again. Handy when one material type runs dry while another overflows.

Remove Level Requirement

Makes twink gear usable on a level-1 character — invaluable for fast power-leveling new Season heroes with pre-staged items.

Augmenting: Caldesann's Despair

The single most important endgame recipe. You permanently add a huge amount of main stat to an Ancient or Primal Ancient item.

• Reagents: 3× Forgotten Souls + 3× Flawless Royal gems (of your main stat) + 1× Legendary gem (rank 30 minimum).
• Bonus: main stat = 5 × the rank of the legendary gem used. A rank-100 gem therefore grants +500 Strength/Dexterity/Intelligence on that item.

[info] Always augment with the highest gem rank you can. A new augment overwrites the old one — so don't waste low-rank augments on items you still plan to upgrade.

[warning] You consume the legendary gem permanently. Always keep a second gem of the same type in case you need one for your GR sockets.

Strategy: Which Power per Build?

A proven rule of thumb: one offensive weapon power, one defensive armor power, one utility/damage jewelry power.

Weapon Slot

• The Furnace — +50% damage to Elites. The push standard for almost every class.
• In-geom — resets all cooldowns after an Elite kill. First choice for speed farming.

Armor Slot

• Aquila Cuirass — 50% damage reduction at high resource. The defensive default for many classes.
• Nemesis Bracers — shrines spawn Elite packs. Top pick for speed-farming materials and XP.
• Illusory Boots — walk freely through enemies. Small but valuable for pushing.

Jewelry Slot

• Convention of Elements (CoE) — a rotating +200% elemental damage multiplier for massive burst in push runs.
• Unity — splits damage with a follower/ally; paired with the follower's Relic of Leadership it's extremely strong for solo pushing.
• Halo of Karini — strong damage reduction when combined with shield/storm skills.

Pushing rule of thumb: damage in the weapon slot, survival in the armor slot, a multiplier in the jewelry slot.

Common Mistakes & Pro Tips

• Mistake: Forgetting the Cube in a new Season. Without it you're missing three legendary effects — get it first.
• Mistake: Extracting items with a bad roll. For percentage powers the source item's value carries over — always extract the best available.
• Mistake: Wasting materials reforging. Only reroll genuine BiS candidates, not every Legendary.
• Tip: Keep several Forgotten Souls on hand for augments — they are the most common bottleneck in the endgame.
• Tip: When gambling, choose the rare item type with the smallest Legendary pool to fish efficiently.
• Tip: Bind a hotkey for the Cube — when mass-extracting at season start it saves an enormous amount of time.