The Inevitability of Rust is the third episode for the Inventor.

In this episode, the Inventor's pieces of equipment are only usable four times through the whole battle, with the uses left indicated by the dice on the top right. Equipment can be repaired through means like Grindstone, however.

On the other hand, equipment can be used multiple times in a turn, since it only breaks once it's out of uses. Once a piece of equipment breaks, it turns into the gadget it's meant to scrap to, and the gadget is re-enabled.

Similarly, the gadget also only has four uses before it becomes a Broken Gadget. However, it only has one use per turn, so ending your turn is required both to replenish your dice and to re-use the gadget.

Upgrading a piece of equipment will reset its uses back to 4 if the equipment upgraded has less than 4 uses remaining. Copying equipment will retain its number of uses.

If you use any equipment that has multiple uses, like Bump+ (2 uses per turn), its durability will only drop after being “fully” used (i.e. Bump+ used twice or Spanner+ used three times).

The Inventor starts with the gadget Focus, which does the same thing as her Limit Break, Focus.

All items list the available equipment and the gadget that it becomes once it runs out of uses.

Floor 1 has three chests. One will contain either one of these items:

The other will always have this item:

The last chest will contain this sword:

There are two apples as well as two chests and one shop on this floor.

Two of these items show up in the two chests on floor 2:

The shop in floor 2 will sell these options for costs of 2, 3, and 4 gold, shuffled randomly.

This floor contains one apple, three chests, and two shops.

One chest contains this equipment:

The other chest contains one of these items:

The last chest contains one of these three items:

The first shop contains these items for 1, 2, and 2 gold, shuffled randomly:

The second shop contains these items:

There are two apples and three chests on this floor.

One will always contain this item:

One always contains this item:

The last chest contains one of these three items:

There are two apples, two chests, one shop, and an upgrade anvil on this floor.

The chest will contain one of these items:

The other chest contains the last of these three items:

The shop sells these options:

If the last boss is Drake, this equipment will appear:

This episode actually contains the most enemy exclusions in the main 36 episodes, likely because stealing multi-use equipment through the Steal gadget didn't work out well in this episode.

The Level 1 enemy Robobot, Level 2 enemies Baby Squid and Mimic, Level 3 enemy Keymaster, Level 4 enemies Aurora, Crystalina, Kraken, the Level 5 enemies Bounty Hunter, Cornelius, Gargoyle, and Paper Knight, and the bosses Aoife, Audrey, Buster, and Madison are not available in this episode.