| Name | CR | CollapseFarm Locations |
| Bestore | ♦12 | Ataraxia’s Haven |
| Bladebreaker | ♦10 ♥12 | Temple of Elemental Evil Part One — (historic) |
| Blight | ♦5 ♥7 ♠9 | The Sunken Sewer |
| Brightbane | ●♦32 | The Ruins of Thunderholme — Inside the mushroom forest, north of the shrine |
| Burrowing Rust Monster | ♦3 ♥5 ♠8 ●♦32 ●♥36 ●♠40 | The Sacred Bounty
Rosemary’s Ballad |
| Corrosion (monster) | ♦7 ♥9 ♠11 | The Iron Mines: Justice for Grust — Inside the rust monster pit |
| Corrosive Rust Monster | ♦16 ♥18 ♠21 ●♦32 ●♥36 ●♠40 | Desire in the Dark
Records of the Past |
| Crumble | ♦3 | The Waterworks — Behind the door locked with the Wisdom Rune |
| Decay | ♦8 ♥8 ♠8 | Sykros’ Jewel — Found in the north passage in the east cave |
| Droaam Ogre Cavalry | ♦14 ♥16 ♠19 ●♦37 ●♥40 ●♠45 | Siegebreaker |
| Enraged Rust Monster | ♦5 ♥7 ♠9 | The Depths of Doom — East side from entrance, after the Wraith
Tempest’s Spine — After the STR lever
Legendary Tempest’s Spine |
| Ferocious Rust Monster | ♦16 ♥18 ♠21 | Rainbow in the Dark — Common enemy |
| Fierce Rust Monster | ♦13 ♥15 ♠18 | Rainbow in the Dark — Common enemy |
| Fissure | Challenge Level + 1 | Lava Caves: Circles of Power — Spawn somewhere in the area when you reach your goal, and make a beeline to the kobold base |
| Gluttonous Rust Monster | ♦3 ♥5 ♠8 ●♦32 ●♥36 ●♠40 | The Haunting of Saltmarsh |
| Greed Monster | ♦20 ♥24 ♠30 | I Dream of Jeets — Back door of the treasure dream |
| Huge Rust Monster | ♦8 ♥11 ♠14 | Ataraxia’s Haven — Rust Monster Beach
Escort the Expedition — South from the 3-traps corridor
Finding the Path — Grouped with Gatekeeper and Marut Inevitable. Red-named.
Hold for Reinforcements
Maraud the Mines — Southwest corner from main room, go south.
Tempest’s Spine
The Library of Threnal
The Threnal Arena
Legendary Tempest’s Spine
The Codex and the Shroud — Phase 5, summoned during Khyber sections |
| Large Rust Monster | ♦7 ♥9 ♠11 | Reclamation — Between the top and middle rooms
Stromvauld’s Mine — Right at the start
Tempest’s Spine — Rust Monster room
The Vault of Night — Path that opens after throwing the Adamantine Coffer in the disposer
Legendary Tempest’s Spine |
| Leech | ●♦24 ●♥28 ●♠27 | In the Belly of the Beast |
| Parasite | ●♦12 ●♥15 ●♠16 | In the Belly of the Beast |
| Renfroe Rex | ♦5 ♥7 ♠10 ●♦36 ●♥40 ●♠46 | Catastrophe |
| Rex | ♦10 ♥12 ♠15 ●♦33 ●♥37 ●♠41 | Assault on the Aerie of the Slave Lords |
| Rust Monster | ♦3 ♥5 ♠7 | Entering the Gate Chamber
Tangleroot Gorge — Inside the scorpion cave
The Depths of Darkness
The Depths of Despair
The Depths of Doom — Spawns on Hard and Elite
Gwylan’s Stand
The Iron Mines: Justice for Grust — At the bottom of the ladder in the second half of the quest if Corrosion does not spawn
The Missing Expedition
The Threnal Arena
Dread Sea Scrolls — guarding the Crest of the Trident |
| Rust Monster Scavenger | ♦8 ♥10 ♠13 ●♦31 ●♥35 ●♠39 | Slave Pits of the Undercity
Assault on the Aerie of the Slave Lords |
| Rustful Stalker | ♦16 ♥19 ♠23 ●♦32 ●♥36 ●♠40 | House of Pain |
| Rusty | ♦7 ♥9 ♠12 ●♦24 ●♥28 ●♠34 | The Snitch |
| Rusty Iron Kitchen Key | ♦15 ♥18 ♠21 | Delirium |
| Scour | ♦8 ♥8 ♠8 | Reclamation |
| Tarnish | ♦5 ♥7 ♠9 | Redfang the Unruled — Long hallway near end of quest |
| Temple Rust Monster | ♦8 ♥10 ♠13 ●♦31 ●♥35 ●♠39 | ToEE: Earth Node
Temple of Elemental Evil Part Two — (historic) |
| The Eater | ♦4 ♥6 ♠9 | The Depths of Despair — May appear in one of three spots: in the corridor before the shrine; in the westernmost corridor; or in the southernmost corridor. |
| The Rust Emperor | ♦15 ♥17 ♠20 ●♦27 ●♥31 ●♠48 | The Vault of Night |
| Well-fed Rust Monster | ♦3 ♥5 ♠8 ●♦32 ●♥36 ●♠40 | Heart of the Problem |
| Xachosian Landwalker | ♥3 ♠6 | Eye of the Titan
I Dream of Jeets
The Dreaming Dark (quest) |
