Destroy a Vault Robots & Index Collection

Destroy a Vault is a robot collection game wrapped around a vault-smashing economy. This Robots & Index Hub explains how the 76-robot Index feeds long-term luck, when you should buy a podium offer, and when you should skip to protect Cash for upgrades. For deep breakpoint math and the path to 62.5%, open Index Luck. Pair both with the robot tier list, getting started, and codes so collection progress never starves your DPS board.

What the Index actually rewards

Every unique robot you unlock permanently marks the Index. Index Luck grants a luck boost for every five unique robots. Filling the entire roster of 76 robots awards a total of 62.5% Index Luck. That passive stack makes later rolls more likely to show rarer tanks and mutated variants—so collection is not vanity; it is a compounding economy buff.

Index progress is separate from which robots sit in your active army slots. You can own a unique for Index credit even if a better mutated unit replaced it on the field. Chase uniques for luck, but deploy the highest effective DPS lineup for Gold income.

Collection goals vs power goals

Split your brain into two modes:

Power mode (early and mid clears)

• Fill slots with the best DPS you can afford.
• Prefer mutated offers and high-rarity chassis from the tier list.
• Spend Cash on Robot Damage, then Robot Battery, before luxury Index buys.
• Use Gems for Mutation Cores on your strongest active robot.

Collection mode (stable base, spare Cash)

• Buy any new unique at a reasonable price, even if it is only C-tier on the field.
• Track milestones every five uniques so you notice Index Luck ticks.
• Reroll aggressively when the podium shows duplicates of low-value Commons you already indexed.
• After the second island, bank duplicates of strong types for fusion instead of selling every extra blindly.

Switch modes often. A brand-new player should stay in power mode until vault clears feel automatic; a mid-game player with spare Cash should drip Index uniques between Damage upgrades.

Rolling strategy: buy, skip, or bank

Rolls put random robots on the podium. You may purchase the offer with Cash or roll again. Smart decisions:

Buy when:

• The robot is a new Index unique and the price will not block your next Damage upgrade.
• Effective DPS (including mutation) beats your weakest active slot.
• You need fusion fodder: three copies already owned, fourth appears, fusion unlocked.

Skip when:

• It is a duplicate Common you already indexed and do not plan to fuse.
• The Cash cost would delay Robot Damage or Battery by a meaningful chunk.
• A mutated high-DPS alternative is likely if you keep rolling with improved luck.

Bank (hold duplicates) when:

• Fusion is unlocked and the type is A-tier or better on the tier list.
• You are one or two copies from a four-of-a-kind fusion.
• The duplicate is not blocking a slot you need for a stronger unique.

Remember: robots created through fusion cannot be fused again. Plan Index + fusion paths so you do not consume the wrong copies.

Mutations and why collectors still care about DPS

Mutations multiply a robot’s DPS. They appear more often as Robot Luck and Index Luck rise. Collectors sometimes ignore mutations to “finish the Index faster,” but that slows Gold and therefore slows the Cash needed to buy remaining uniques. The efficient path is:

1. Raise Damage / Battery so clears print Gold.
2. Smelt Gold into Cash.
3. Buy uniques when cheap; buy mutated power when expensive but transformative.
4. Convert Gems into Mutation Cores for your carry tank.
5. Return to Index hunting with better luck and a richer wallet.

That loop is why this hub and the tier list must stay cross-linked—collection without DPS is slow, DPS without Index Luck hits a rarity wall.

Fusion as a collection sink

Fusion unlocks with the second island. Feeding four identical non-fused robots produces a stronger version and removes those four from the raw pool of spare copies. Use fusion to:

• Clean inventory clutter from robots that roll too often.
• Promote a favorite type into a board mainstay.
• Convert “useless” duplicates into measurable DPS.

Do not fuse away your last indexed story if you somehow still need visual confirmation—but Index credit normally persists once unlocked. Prefer fusing types you already indexed and still value in combat.

Practical Index roadmap

1. Tutorial slot + first purchases: any robots that let you smash the first vaults.
2. First Damage / Battery upgrades from the boards.
3. Buy every cheap unique until you hit the first few Index Luck breakpoints (5, 10, 15…).
4. Start skipping weak Commons; chase Uncommon+ and mutations.
5. Unlock island two → begin fusion projects for frequent high types.
6. Push toward the full 76 for the 62.5% Index Luck ceiling while keeping an S/A-tier fielded army.

Redeem promo codes such as RELEASE, UPDATE, and 100K whenever they are live—Cash and Gems accelerate both collection buys and Mutation Cores. For patch-driven roster changes, watch the updates hub. For a full systems map, open the Destroy a Vault wiki overview.

Common mistakes

• Buying every Common forever and starving Damage upgrades.
• Ignoring mutated mid-rarities because the Index label looks “lower.”
• Spending all Gems on random cores instead of your best tank.
• Fusing before island progression or attempting to fuse already-fused units.
• Treating Index Luck as optional endgame fluff—it is a mid-game multiplier engine.

Stay disciplined: unique when cheap, power when contested, fuse when ready. Your Index will climb, your luck will stack, and your vault clears will keep funding the rest of the roster.

Related Destroy a Vault pages

• Index Luck — every-five milestones, 62.5% ceiling, buy vs skip
• Read the upgrade priority guide for deeper tactics.
• Read the mutations guide for deeper tactics.
• Read the robot fusion guide for deeper tactics.
• Read the economy guide for deeper tactics.