Ghoul

Ghouls are humans that have been warped into powerful, twisted combat entities with very few needs. Ghouls can appear as both enemy units and become a part of your colony. Ghouls that are part of your colony can only eat raw meat and fresh corpses. Captured Ghouls do not require food.

Acquisition

Ghouls cannot be recruited. Enemy ghouls can only be killed or captured as part of operating a holding platform.

To create a friendly ghoul, you must research Ghoul Infusion in the Anomaly tech tree. A medical operation becomes available that irreversibly converts a colonist or prisoner into a ghoul at the cost of 30 bioferrite and 1 shard. This will damage relations with the faction of the patient, should they belong to one. Prisoners turned into Ghouls become friendly player controlled Ghouls.

The Anomaly starting scenario begins with a ghoul colonist.

Summary

A ghoul is effectively a colonist that is limited to only melee attacks. Ghouls cannot wield weapons or apparel. Backstories, traits, and genes that disable violence become inactive. All Ghouls are capable of violence and have a Melee and Shooting (even though ghouls can't shoot) skill. All of the ghoul's other skills are disabled. If a ghoul had a passion for Melee and/or Shooting in life, it retains it as a ghoul.

Ghouls can't do any work. Ghouls retain the natural attacks of a human, but also gain a left and right claw attack and an additional bite attack.

All ghouls are given two hediffs that implement the majority of the stat changes experienced by ghouls. These hediffs are "Ghoul" and "Regeneration".

Ghoul:

Pain: ×0%
Max Nutrition: 2
Psychic sensitivity: ×0%
Minimum Comfortable Temperature: −40
Maximum Comfortable Temperature: +40
Minimum Containment Strength: +35
Talking: ×0%

Regeneration:

Regenerate 100HP/day^{[Detail needed]}
- Seems to focus on a single injury at a time, healing it completely before moving on to the next until all injuries are removed
- Selection mechanism for the next injury to heal is currently unknown^{[Detail needed]}

Ghouls can only eat raw meat and fresh corpses. They will automatically try to eat available food in their assigned zone. Friendly ghouls that are not fed have an increasing chance to become hostile. Ghouls will happily eat insect meat, human meat, and twisted meat.

Ghouls require no sleep, no recreation, no comfort, and have no item needs besides food. They regenerate 100 health per day, automatically regrow lost limbs, and rapidly cure negative health effects. Ghouls can't have any relationships and don't have mood.

Ghouls do not age at all, even if not yet at maturity. Note that this means that ghouls created from younger pawns will never have the full body size and body part health of an adult. Ghouls can have age related heart attacks.

Ghouls can be restricted to zones and drafted as normal. In combat, they can be directly commanded to melee attack. Ghouls have their pain set to x0%, allowing them to fight until their health is fully depleted or they are incapacitated due to damage to their body. As mentioned however, damaged limbs and organs will regenerate even if downed, unless they are dead.

Ghouls will fight adjacent fires, but do not seek out fires to extinguish. Ghoul pyromaniacs and Ghouls Incapable of Firefighting retain their incapability to fight fires.

Ghouls retain the traits they had in life. While most won't be relevant to a ghoul, they can benefit from traits like Jogger and Brawler. A Tough ghoul with Ghoul plating takes only 25% damage (19% with Robust gene). Such a ghoul can freely walk in unnatural darkness and solo kill all spiked monoliths, kill Megasloth 1-on-1, and tank a Thrumbo under friendly fire.

Once converted, the pawn is no longer counted as a full colonist for things like the recluse trait.

Ghouls will also retain their genes, though not all will remain effective. Genes that affect stats, traits, and aptitudes will remain active. Hemogenic genes, chemical dependencies, ability-granting genes, and violence disabled will become inactive. Cosmetic genes that add body parts will remain visible, while genes that change skin/hair color, hair type, head shape, or fur will not.

Additionally, a large number of still-active genes will become either redundant or ineffective due to the inherit qualities of ghouls, like reduced pain, aggressiveness, any non-violent aptitude, and any degree of psy-sensitivity.

Entirely new xenogerms can be implanted into ghouls.

Alternatively, the ability for ghouls to undergo gene extraction combined with the low cost of ghoul resurrection serums allows ghouls to be used in the efficient purification of genes from multi-gene genepacks. Note that ghouls who are killed via gene extraction will have their xenotype set to Baseliner, however they will retain any endogenes ("germline genes"). Thus in order to safely farm genes from a ghoulified Sanguophage, Hussar, Genie, or Highmate, they must be killed through any other means before being resurrected.

Ghouls can be assigned to travel as part of a caravan.

Despite the in-game description, colonists do not gain negative mood for being near a friendly ghoul, however they will experience a negative mood if a loved one becomes a ghoul or spawns as a ghoul.^[Detail]

Upgrading ghouls

Ghouls can have standard prosthetics such as bionic legs and Archotech arms installed via medical operations. In particular, their sole need being nutrition coupled with immunity to carcinoma makes a nuclear stomach an extremely cost-effective upgrade.

By researching the Ghoul enhancements technology in the Anomaly tech tree, you can add special bioferrite prosthetics to a ghoul:

Adrenal heart — Passively increases hunger, grants an ability to gain a burst of ×0.7 attack cooldown and +4.00 movement speed for 15 seconds. The cooldown is 29.17 seconds.
Corrosive heart — Allows the ghoul to spew acid on a 2 hour cooldown, but only has 85% part efficiency
Ghoul barbs — Increases melee damage by ×150% at the cost of −0.25 speed
Ghoul plating — Incoming Damage Multiplier ×0.5 at the cost of −0.75 speed.
Metalblood heart — On a 6 hour cooldown, gain the Metalblood hediff for 40 seconds, which gives ×50% damage resistance and ×400% fire and burn vulnerability. This hediff does not stack with the metalblood serum.

Ghouls cannot use drugs but can use serums. As ghouls aren't affected by mood, this can make juggernaut serum especially effective for them.

Analysis

Ghouls are incredibly powerful guard dogs and melee attackers:

With melee upgrades of ghoul barbs, power claws, juggernaut serum, and strong melee damage gene, their attacks will destroy any body part of any human they hit (no matter the armor), frequently one-hit killing enemies in cataphract armor.
With metabolic upgrades of nuclear stomach, +5 metabolic efficiency, and robust digestion gene, they need less than 4 twisted meat per day to survive.
Due to their regeneration and the affordability of ghoul resurrection serum, it's safe to use ghouls as tanks, or even let them die in combat.

Converting a colonist into a ghoul is a good way to make use of an otherwise terrible pawn or a colonist you can't save from death. The converted ghoul will quickly regrow lost limbs and self-cure detrimental health conditions.

A ghoul makes excellent bait to lure revenants and sightstealers, as they can remain patrolling outside forever.

While requiring direct control, Ghouls can still help with some work in colony. While drafted they can be used to hunt animals (though they will not carry the corpses back). They can also be used to fight fires. In Anomaly starting scenario the Ghoul allows you to skip early defences, indirectly reducing amount of work that needs to be done.

Be especially careful when engaging enemy ghouls in melee combat. They will not be forced down due to pain, so they will fight much longer than regular human raiders.

Body part weapons

Ghouls can also make effective use of body part weapons like the power claw. As they cannot hold conventional weapons, ghouls can only make unarmed attacks. Implanted weaponry offers them a powerful upgrade, making their already powerful strikes terrifyingly effective in combat.

Combing Ghoul barbs and the strong melee damage gene stack with the increased dps of the implants and offer dps comparable to high tier melee options.

The power claw features the highest damage, albeit with a small movement speed penalty.

If it is not possible to give a ghoul two power claws, it is better to give them one power claw and one wooden hand than to keep the normal hand. This is because it would choose the weaksauce normal fist 25% of the time, thus reducing the damage, but with a wooden hand it will only use the power claw.

Genetics

Ghouls primarily benefit from genes that improve their Incoming Damage Multiplier, melee skill and damage, movement speed, and achieving a good metabolic rate to reduce meat consumption. Ghouls will inherit genes from their underlying xenotypes, meaning that some make for better ghoul candidates than others.

Keystone Genes
Gene	Improves	Metabolic Cost	Commentary
Robust	×75% Incoming Damage Multiplier	−2	Reduces damage taken by ghouls, improving their capability to soak incoming damage for longer.
Strong melee damage	×150% Melee Damage Factor	−2	Increases damage dealt by ghouls

Good Genes
Gene	Improves	Metabolic Cost	Commentary
Naked speed	+0.1 Movement speed	+2	Slight increase to movement speed while giving free metabolic efficiency
Fast runner	+0.2 Movement speed	−3	Double the movement speed bonus of Naked Speed
Very fast runner	+0.4 Movement speed	−5	Huge increase to movement speed, but very metabolically costly.
Strong Melee	Melee Skill +4	−1	Improves Melee skill which boosts melee hit chance and melee dodge chance
Great Melee	Melee Skill +8	−3	Larger Improvement to Melee skill
Unstoppable	Stagger Time Multiplier ×0%	−2	Removes stagger from receiving damage
Fire Resistant	Flammability ×10%, Flame damage ×25%	−2	Resist flame damage and avoid being set on fire
Robust Digestion	Raw Nutrition Multiplier ×180%	−1	Increase nutrition given by raw meat
Elongated Fingers	Manipulation ×110%	−1	Slightly increase manipulation, which affects melee hit chance
Smooth Tail	Manipulation +5%	−1	Slightly increase manipulation
Superfast Wound Healing	Injury Healing Factor ×400%	−3	Quadruple the normal healing factor to roughly 25 HP/day

The negative effects of the genes below don't affect ghouls at all, thus they can be used to improve their metabolic efficiency

Free Metabolic Efficiency
Gene	Changes	Metabolic Cost	Commentary
Awful Skill	Skill −8	+2	Ghouls only use Melee skill, any other skill can be ignored
Poor Skill	Skill −4	+1	Ghouls only use Melee skill
Hyper-aggressive	Mental Breaks and Social Fights	+3	Ghouls don't social fight or have mental break
Aggressive	Mental Breaks and Social Fights	+2	Ghouls don't social fight or have mental break
Very Unhappy	Mood Penalty	+5	Ghouls are unaffected by mood penalties
Unhappy	Mood Penalty	+3	Ghouls are unaffected by mood penalties
Deathrest	Need for deathrest	+6	Ghouls don't need deathrest
Hemogen drain	−8 Hemogen per day	+6	Ghouls don't need hemogen
Pyrophobia	Fleeing fire mental break	+4	Ghouls don't have mental breaks

Hunger management

Ghouls don't get cancer, so the nuclear stomach is an ideal way to keep them from berserking from hunger.

The Robust digestion gene synergizes very well with the Ghouls natural diet of raw meat, but don't work with corpses^[Verify]

Ghoul made from body-mastery creepjoiner don't need to eat at all, but removing of sleep and comfort needs became redundant.

Medical quirks

Because ghouls rapidly regenerate their organs, you can harvest their organs before turning them into a ghoul:

Harvesting a spare lung and kidney is possible for normal pawns.
You can harvest all six organs from a sanguophage.
If you have a detoxifier lung and kidney, you can install them to the pawn and harvest both natural lungs and kidneys. Then after the ghoul has finished regenerating, you can safely remove the artificial organ.

Becoming a ghoul does not remove duplication sickness, paralytic abasia or cirrhosis. However, if you then euthanize the ghoul and revive them with a ghoul resurrection serum, it does remove the sickness but won't cure the paralytic abasia.

The Ideal Ghoul

Here is the setup for the best ghoul that can be mass-produced by an advanced colony. The follow features are very hard to achieve; but once achieved, they can be duplicated using the Corrupted obelisk any number of times:

Void touched: available during the Anomaly ending, gives 100 hp/day regeneration on top of ghoul's regeneration.
Level 20 melee skill: massively improve melee hit and dodge chance.
All keystone and good genes listed above, except for Strong Melee and Great Melee, as they have already been covered by the base melee skill. Other metabolically efficient genes should be included to bring the efficiency up to +5.
Tough trait: Incoming Damage Multiplier x50%.
Jogger trait: Move Speed +0.4.
Nimble trait: Melee Dodge Chance +15. This gives a small increase in the final melee dodge chance and can be skipped.
Trauma savant: arguably the hardest to achieve, while only giving a very small improvement for melee hit chance.

Once you have a colonist or slave with these features, duplicate them using the Corrupted obelisk and turn the duplicate to ghoul, keeping the original. The ghouls can have these body parts installed to upgrade them further:

Ghoul plating: Incoming Damage Multiplier x50%, while Move Speed -0.7
Ghoul barbs: Melee Damage Factor x150%, while Move Speed -0.25
Adrenal heart: gives a massive buff for move speed and melee damage when used. This is superior to the metalblood heart if you have a steady supply to produce your own metalblood serum; while the corrosive heart's attack has fixed damage and wouldn't scale well with the other upgrade we have.
Power claws: greatly improves ghouls' melee damage.
Nuclear stomach: Food Consumption x25%.
Stoneskin gland: sharp armor +70%, blunt armor +30%, heat armor +50% while moving x85%. This will also be the final armor values of the ghoul.
Regular Juggernaut serum administering: Move speed +0.5, Melee Damage Factor x150%, Injury Healing Factor x200%.
Metalblood serum administering: Incoming Damage Multiplier x50%, while flame and burn weakness x400%. The flame weakness is cancelled out by the fire resistant gene.
Healing enhancer: natural healing factor x150%.
Bionic eyes and legs: improve melee hit and dodge change, and also move speed. These can also be skipped without reducing the power of the ghoul by much.

Note that power claws, bionic eyes and legs may be destroyed in combat if they take too much damage, so be ready to replace them if you decide to give to the ghoul. Other body parts are less likely to be lost as the ghoul are more likely to be downed or die before that. Overall, the ghoul would have these stats:

Daily Food Consumption 0.32 with Raw Food Multiplier x180%: this means they need only 3-4 twisted meat per day to live.
Healing 200 hp/day, plus roughly 75 hp/day from the 800% Injury Healing Factor and 150% Natural Healing Factor.
Incoming Damage Multiplier 9.4%: this improves the amount of damage ghouls can take by over 10 times, which means it takes roughly 2925 damage point/day, or 2.9 point/s (after armor and melee dodge) just to negate the healing effect of the ghoul
Melee AP 111%.
Melee attack damage 74.25, for a DPS of 34.41 (without Ghoul frenzy), or 49.16 (with Ghoul frenzy): even for enemy with cataphract armor, the ghoul will tear off any body part they hit and instantly kill if they hit a vital one.
Melee Dodge Chance 38%.
Move Speed 4.7 (without Ghoul frenzy), or 8.42 (with Ghoul frenzy), or 10.86 (with Ghoul frenzy and psychic focus).