Deep Dive into RimWorld Biomes

Dive deep into the Anomaly DLC for RimWorld. Discover new entities like Fleshbeasts and Sightstealers, understand the Monolith's role, and learn about ambient horror threats.

Anomaly is a horror-themed DLC for RimWorld that introduces mysterious threats, containment facilities, a new research tree, psychic rituals, new gear craftable from a new resource, and a new endgame. It was released on April 11, 2024.

Darkness stirs on the rim. Survive flesh infestations, cultist attacks, shambling undead, blood rains, invisible hunters, and other sanity-shredding perils. Capture and study entities to harness the power of the void. Conduct psychic rituals and awaken an evil machine god.

Your colonists accidentally awaken a dark monolith and provoke an insane machine-mind of unfathomable power. Its terrifying manifestations begin to haunt the world. Survive these strange happenings as you study the new phenomena and learn how to end the madness.

The Monolith is a structure that is found on the map at the start of the game, or after the quest Strange Signal if the monolith is not currently present on any player map tile. It starts off deactivated, and becomes activated once a pawn is assigned to investigate it and all warnings are ignored.

After the monolith becomes activated, more entities are able to appear. The player is given access to view the entity codex. Activation sets the monolith to level 1. Increasing monolith level is accomplished by discovering entities of the current Entity Codex Tier and then interacting with the monolith.

There are 8 entities to discover at level 1, 17 at level 2, and 2 at level 3. Reaching level 2 monolith requires discovering 7 of 8 level 1 entities. Level 3 monolith requires discovering 12 of 17 level 1 or 2 entities.

Entities are the major threats of the Anomaly DLC. Most Entities will not appear until a colonist has finished investigating the monolith. Entities will appear in the Entity Codex after being discovered. A higher level monolith will cause more dangerous entities to appear.

Entities can be studied by incapacitating them and placing them within a containment cell. Colonists will be automatically set to study them with the Dark Research job, which will advance progress in the Anomaly Tech Tree.

Ambient Horror: The monolith does not appear. Any Anomaly threat can occur, but Anomaly threats will be rare by default. Good if you want to interact with Anomaly expansion content without it being the focus. NOTE: The monolith endgame cannot occur in this mode.

The frequency of anomaly major threats can be adjusted in the custom difficulty options. The default settings are 8% Anomaly Threats while the monolith is inactive and 30% Anomaly Threats after the monolith has been investigated. These sliders do not affect Minor anomaly incidents like Small Shambler Swarm, Creepjoiner Arrival, and Distress Calls.

Ambient Horror is only selectable before the game starts and cannot be changed thereafter.

Basic Entities

• Void monolith — A monolith of unknown age, purpose, and construction. Its smooth surface is etched with lines that twist and writhe in unsettling patterns.
• Harbinger tree — A gnarled tree that grows a flesh-like covering. Harbinger trees are capable of feeding on corpses and raw meat, and will consume those placed nearby. If well fed, the grove will continue to grow. In a tribal myth, these trees are the emissaries of a mad, shapeless god who rules an endless black ocean. The myth ends after the shapeless god reaches up from the water and tears down the sky.
• Fleshbeast — Hideous creatures composed of masses of cancerous flesh. Some contain multiple nervous systems, allowing them to split into smaller fleshbeasts.
• Sightstealer — Emaciated and misshapen humanoids. Their arms end in sharp, curled claws formed from bioferrite. Sightstealers are fragile, but use psychic influence to render themselves invisible until they get close to their victims. They are known to emit haunting screams as they gather on their terrible hunts.
• Shambler — Corpses reanimated by microscopic archites. Shamblers are slow, mindless, and will attack relentlessly. Unless captured, shamblers die from metabolic exhaustion after several days.
• Ghoul — A person implanted with an archotech shard and twisted by dark psychic influences into a jittering murder machine.
• Gorehulk — A monstrous creature that resembles a massive, painfully swollen human with randomly reconfigured body parts. Near its top is a stretched face that watches its victim with dead eyes. Hundreds of sharp keratin spines protrude from the gorehulk's skin. It can launch these spines to spear its victims at a distance. However, its awkward fleshy body is less effective at causing harm up close. It's hard to know whether this is a human that was horribly distorted by the influence of the void or a poor imitation of humanity created from scratch by some evil intelligence.
• Death pall — A corpse-gray cloud composed of microscopic self-powered archites created by some unknown superintelligence. When they land on dead flesh, they enter the body and reanimate it to create a shambling imitation of life.

Advanced Entities

• Pit gate — A massive, foreboding hole that connects the surface with a dark network of underground caves. It is possible to climb down into the caverns below.
• Dreadmeld — A gargantuan amalgamation of dozens of smaller fleshbeasts linked together by a loosely shared central nervous system. It uses its massive claws to dig tunnels through solid rock. Fleshbeast dreadmelds are rarely seen above ground, instead sheltering in caverns built from living flesh. They share a psychic connection with the flesh used to create their burrow.
• Fleshmass heart — The primary organ of a fleshmass infestation. The heart gathers material through roots extended into the ground. Once it has collected enough, it spreads fleshmass around itself in a spurt of cancer-like growth. It will keep growing until it consumes everything. The heart grows fleshmass spitters. These defensive organs can spit acid long distances. The heart will also generate fleshbeast defenders to protect itself. Ultra-rapid regeneration makes the heart nearly invulnerable. It can only be killed by analyzing samples taken from the nerve bundles that form within its growing mass.