Corruption is the means by which the PC is tainted by the essence of Chaos. The PC can be corrupted by being damaged by a creature of chaos, triggering a corruption trap, eating the corpse of a corrupted creature, drinking a potion of raw chaos, activating a staff of corruption dissemination, or local background corruption. Some powerful artifacts of chaos will corrupt the PC simply by being in his/her possession; equipping them will amplify the effect.

Each new corruption means that PC gains new abilities, most of them granting some kind of advantage in exchange for some disadvantage. Some of these abilities are quite powerful, but beware: if the PC becomes fully corrupted, they will be transformed into a writhing mass of primal chaos, and the game will end.

PCs get one corruption for each 1000 corruption points (CP) they accrue. Any incoming corruption is adjusted by the following factors:

There are a total of 35 different corruptions, but the PC have at most 18 at one time. The corruption pool will always include Poison hands, Mana battery, and Very light. Apish look will always be the final corruption. Otherwise, the other corruptions and order of corruptions in the pool is random. However, the 18 corruptions in the pool will remain the same unless all corruptions are removed.

In addition to the specific special effects of corruptions, with a certain number of corruptions, the PC will get bonuses to Strength, Dexterity, Toughness and Mana, and a penalty to Willpower, depending on alignment. The gains or losses to such stats are as follows:

  • If chaotic: (number of corruptions)/2 point(s)
  • If neutral, (number of corruptions)/3 point(s)
  • If lawful, (number of corruptions)/4 point(s)

Table of corruptions[]

Name Benefits Drawbacks Keeper score Specific notes
Acid blood Acid immunity, blinds and damages monsters who damage the PC in melee Blind monsters with the teleporting ability will teleport every time they move, making them hard to track. Cats can kill themselves by attacking the PC. 5 (4)
Black eyes See invisible, +3 Pe None 5
Devour Order Eating corpses of lawful monsters gives a 1d100 speed boost None 4 Lawful corpses are somewhat hard to obtain/farm. Still, there is no downside to keeping this corruption even for lawful characters as it has no drawbacks.
Gills Water breathing -3 Ap 4 Definitely keep this at least until you've visited the Water Dragon Cave and the Water Temple.
Sulphuric breath Drakeling-like acid spit -4 Ch 4 Can be used to manipulate satiation, being one of the few ways to force-remove the Bloated status. Drakelings already have this, but a minor penalty to Charisma is relatively harmless as far as a typical corruption goes.
Antennae Sometimes reveals map close to the PC -4 Ap 3 Map reveals are too rare to have a significant influence.
Bloody sweat +5 speed -2 Ch, -4 Ap 4
Bronze bones +3 PV -2 Dx, -2 DV 4 Extremely good early on; later on swapping DV for PV likely does not matter.
Chaos whisper +4 Le, +2 Ma -6 Wi 2 Reasonable trade-off if your character needs Learning; outside of the early game, Willpower is more important.
Babbling mouth +8 Le, periodically acts like wand of wonder casts Stealth impossible, -6 Ch, -4 Pe, -6 Ap 2 Casts drain all PP so this is a must-remove for casters by mid-game; might cause problems by casting attack spells on residents of Dwarftown, Casino level monsters, etc. Learning boost might be beneficial for borderline casters to learn some spells. Wish is posible.
Bulging cranium +6 Le, +4 Wi -3 To, -4 PV, -6 Ap 4 (3) Good for spellcasters, bad for melee characters.
Stilts Decreases movement energy cost by 25% -4 PV, -6 Ap, reduces kick damage 5 The energy cost discount is well worth 4 PV in most cases. Somewhat weaker for characters who have movement cost reductions through class powers.
Scales +8 PV -6 Dx, -4 Ap 4 Extremely good early on, but still a fair trade later.
Thin and nimble +6 DV, reduced PC weight Increased hunger rate 5 Food for DV is an excellent trade. Helps with entering the Quickling Tree and climbing down the Rift.
Rage +6 melee damage -9 DV 3
Astral attunement Teleportitis Teleportitis 4 (1) Depends on how you value teleportitis and whether you have teleport control. Assuming they have the latter, strictly ranged characters as well as those aiming for victory in fewer turns might find this corruption indispensable.
Extra eyes +6 Pe -6 Ap 3
Very light +4 Dx, +20 speed, reduced PC weight -6 St, -6 To, -6 Ap 4 (3) Needs to be evaluated in each individual case. Some late game ultra-goers can probably opt for speed over Strength and Toughness (especially since Toughness has diminishing returns), but in a fast game the negatives are significant... but so are the positives. Helps with entering the Quickling tree and climbing down the Rift.
Horns +3 damage for melee attacks -4 Ap 3 Not worth removing individually, but not really worth keeping either.
Hooves +8 kick damage -6 Dx 2 (4) Quite good if using kick attacks, but this is usually not the case by the time the PC receives their first corruption. At least the downside isn't crippling.
Healing tissue Gives ~20hp per 100 turns Occasionally leaves permanent scars; -1 Dx and/or -1 Ap per scar (even after removing the corruption) 3 (4) Good early on and if you play fast (for a game finished in the ~50k turn range healing likely outweighs scars).
Maggots +4 DV, spawns tame worms -6 To, -2 Ch, -4 Ap 1 Toughness is one of the most important stats, no real bonuses to compensate.
Merged eyes +4 Pe (blocked by headgear) -2 Ap, -2 Ch, -1 melee to-hit, -4 ranged to-hit 2 Not worth removing individually, but not really worth keeping either.
Thorns Improves base unarmed damage from 1d3 to 3d3 -2 Dx, -3 Ap 2 Unarmed specialist monks and beastfighters get no benefit at all.
Mana battery Drains wands for more max PP, reduced spell cost Drains wands and staves 1 (3) It's extremely annoying for melee character as certain areas of game are lot of easier with a well-boozed wand of fireballs; casters might keep it, especially if they lack class powers reducing casting costs (necromancers, paladins). Quite desirable for a PC aspiring to become an Archmage.
Mists of ChAoS See invisible -10 Pe 2 (3) Early on losing 10 perception might be hard to compensate, later on PC is likely to have a means of see invisible anyway.
Cold blood Drakeling-like relation to heat Drakeling-like relation to cold, -10 speed, -2 Dx, -1 Ap 2 (4) It's likely positive in the ToEF or the occasional red dragon vault due to high speed gains, but base -10 speed makes it bad everywhere else.
Unholy aura +6 DV -10 Ch, terror aura 2 (4) Since the aura applies to non-hostiles, it depends on the game stage. If you are in the middle of Thrundarr's quests, this is horrible. Mid-game it might cause problems with shopkeepers, HMV, etc. If you are on the final dive towards the chaos gate, it's free DV for anyone except pet and companion users who might want to get rid of it at any point regardless.
Tentacle mouth +6 Dx -15 Ap, casting/speaking failures 3 (1) Decent for non-casters, although the severe Appearance penalty means subsequent corruptions will come faster. Interacting with NPCs is still possible, but annoying. Casters should remove it ASAP.
Poison hands Poisons monsters in melee Turns potions into poison, curses food 1 (4) Effects are canceled while wearing thick gauntlets; high priority to remove if you do not have any (it's often a good idea to keep spares stashed on a regular route or in inventory as they get destroyed easily). Useful in conjunction with Potion belt (provided you have thick gauntlets), as it easily produces big stacks of potions of poison to be transformed with potions of exchange.
Hate the sun Periodically casts Darkness Periodically casts Darkness 2 By mid-late game it is more annoying than dangerous, but it does not provide any real benefit in the long run.
Apish look +3 St -1 Le, -1 Wi, -2 Ch, -3 Ap 3 (1) Periodically kicks in, giving +1 St, To and -1 Le, Wi, Dx, Ch, Ap, which is cumulative and not removed with the corruption. If you are a caster, this reduces Le and Wi which you need; if you are a melee fighter, this gives +St and +To which is beneficial. This is the final corruption received, so it may be necessary to remove to avoid dying to corruption.
ChAoS hands None Corrupts monsters and heals corrupting monsters 2 (3) If you are a primary caster this does not matter; rather bad for melee fighters, especially in areas like D:50.
Decay +10 Wi Greatly slowed HP regeneration, -5 St, -5 Ap, -10 speed 1 (2) Casters with good healing spells might want to keep it in rare situations where the Willpower bonus allows reaching the next range threshold; highly undesirable due to speed and regeneration penalties otherwise.
Stiff muscles +2 St, +4 PV Increases the energy cost of all actions by 1.5x 1 Any action you take is 1.5 times slower. Remove ASAP.

Score explanation:

1: always remove ASAP;

2: remove, unless there are reasons to keep it;

3: neutral or highly context-dependent;

4: keep, unless there are reasons to remove it;

5: always keep.

Version History[]

In 1.2.0 p4, 17 new corruptions were added.

In 1.2.0 p7, characters began to receive attribute modifications based on the number of corruptions possessed.

In 1.2.0 p21, Appearance began to have an effect on corruption. High Appearance reduced both the amount of corruption gained from all sources, and the amount of corruption removed by items.

In 3.3.0, high Appearance was changed to increase the effectivity of corruption removal.