Horror in Fallout 2d20: A Fan-Made Supplement

By Idashroomcloud

There are many things in the Wastelands of Fallout that could drive a person to the edge of sanity, or perhaps
even beyond. Hostile mutants of terrifying visage, irradiated hellscapes, mind-altering drugs and hallucinogens left
behind by ancient, nefarious corporations, and the primal fear that such things might induce in all but the most
stout-hearted individuals are but a few examples.

It is that fear, the terrible things that cause it, and the mind-warping effects it can have that I hope to capture
and quantify in this supplement. Please be warned that some of the items in this supplement can be considered
sensitive or undesirable to some players, and its inclusion in a campaign should be discussed with the
players beforehand.

The default skill test combination used for resisting Horror in this supplement is Intelligence + Survival. While
this is the closest I could come up with, I understand that some GMs may not wish to feed the Survival meta, or restrict
something as potentially impactful as Horror to a single attribute. With that in mind, I encourage you to experiment with
combinations that fit your campaign. You could even go to the extent of including a new skill designed specifically for
resisting Horror. (Self promotion: The custom Character Sheets that I created for the community already include space
for up to 2 custom skills, if you decide to take that route.)

Finally, this supplement is designed to enhance the roleplay in your campaign. While most of the psychoses
and manifestations presented in the tables contain mechanical detriments, it is the narrative implications that can have
the most impact, if your players are willing to engage with them. I encourage the GM and players to lean heavily into
the roleplay, and breathe life and depth into their characters and how they overcome (or don’t overcome) the myriad
horrors that plague the post-war world of Fallout.
 MADNESS
Madness is a numeric score assigned to each player character on an ongoing basis as they are exposed to
elements of the wasteland that might break their minds. This could be something as seemingly innocuous as a horde
of hungry ghouls, or something as unfathomably terrifying as a vision of Ug-Qualtoth. Whatever it may be, the GM will
assign it a value on the Madness Scale, shown below.

Each time a source of fear is encountered by the Player Characters, or at any time the GM deems it
appropriate, the players must roll an Intelligence + Survival test to keep madness at bay. If the test is failed, they gain
Madness Points equal to the Madness Value of the event, which increases their Mad-O-Meter score (see the
Mad-O-Meter chapter).

It is not recommended that these skill tests be required too frequently. Personally I advocate no more than 1-3
rolls per session, using only the most notable events from the narrative as the cause, otherwise players risk
accumulating fear at a faster rate. However, this is solely at the discretion of the GM. This supplement is meant to
provide only the framework for horror’s inclusion.

Madness Examples Difficulty

Value

1 - Being confronted by mutants 1

Minimal - Finding the remnants of raider or mutant activity
Fear - Entering a hostile or fear-inducing environment / region / location

2 - Experiencing basic Wasteland horrors for the first time (mangled corpses, 1
Notable mutants/ghouls, a radstorm, etc.)
Fear - Being chased by mutants or monsters
- Actively witnessing raider or mutant atrocities
- Being in the dark and feeling intensely uneasy / afraid
- Seeing a hideously deformed creature (floaters, centaurs, etc.)

3 - Witnessing a Player Character’s death 2

Major Fear - Witnessing an important friendly Non-Player Character’s death
- Being actively pursued in the dark
- Encountering a monstrosity while in a hostile or fear-inducing environment
- Encountering a unique & grossly mutated abomination (Mirelurk Queen, Behemoth,
etc.)

4 - Witnessing anything otherworldly / paranormal 3

Terror - Encountering extremely dark Vault experiments (Gary, Vault 22 plants, etc.)
- Experiencing an intense, vivid, & terrifying hallucination

5 Witnessing something uniquely, abjectly horrifying (Ug-Qualtoth, alien invasion, etc) 4

Abject
Terror
 TEMPORARY PSYCHOSIS
When making their Intelligence + Survival skill test to stave off Madness, a PC may roll complications. If they
do, they will suffer 1 instance of Temporary Psychosis. Additional complications do not generate additional psychoses.
If a PC is afflicted with Temporary Psychosis, then either the GM or player may roll 1d20 to determine the result.
Alternatively, the GM may select the Temporary Psychosis that best fits. Temporary Psychoses may be acquired even
if the player succeeds on their Madness Test.
Temporary Psychoses lasts until the end of the scene, after which the PC must pass an INT+Survival test with
a difficulty of 1 to overcome it. If they fail, then the effect persists for the next scene, after which it dissipates on its
own. Players and GMs alike are advised to lean into the roleplay of these psychoses and make each encounter a truly
terrifying and memorable one.
If the situation allows, other PCs who are not affected by a psychosis of their own may assist the affected
player with their Survival test to overcome it. The assisting player rolls INT+Medicine by default, but this may be
adjusted by the GM. However, both the assist and the skill test to overcome the psychosis can only be made at the
end of the first scene, as an affected character is too distraught during the scene to acknowledge any attempts at
overcoming their fear.

Result Effect

1 Panic: The PC must Sprint away from the source of their fear using their first action, up to Extreme range.
At this point they may stop fleeing, but they may not move closer until the source of the fear is removed or
overcome. If the source of the fear is omnipresent or environmental, they hide instead, using whatever
means are available. They may attack, but the difficulty and complication range increase by +1.

2-3 Mental Fixation: The PC’s mind is overcome with thoughts of all kinds related to the source of their fear.
The difficulty of all INT tests is increased by +1 as they lose the ability to focus their thoughts.

4-5 Hyperventilation: The Difficulty of STR tests is increased by 1 as the PC begins breathing rapidly and
uncontrollably.

6 Inescapable Doom: The PC is overcome with a feeling of intense dread & immediately loses 1 Luck point,
if able. If they have no Luck points, then they may not restore one with a trinket during the current quest.

7 Cold Sweat: the PC immediately drops all items in their grasp as their body is coated in sweat. The
Complication Range of any action taken is increased by +1, as holding onto items becomes more difficult.

8-9 Shaking: The difficulty of AGI tests is increased by 1 as the PC’s body quakes with fear.

10-11 Nausea: The difficulty of END tests is increased by 1 as the PC is stricken with intense abdominal pain.
Vomiting may ensue at the GM’s discretion.

12-13 Faint: The PC collapses on the ground, unconscious, and does not rise unless they pass an
END+Survival test with a difficulty of 1, or another character uses a Major Action to awaken them (no test)

14-15 Tunnel Vision: the difficulty of PER tests for anything not directly related to the source of the PC’s fear is
increased by 1.

16-17 Startled: The PC is in shock for a moment. They stare ahead, unresponsive for 10 seconds. If this occurs
during or right before combat, they cannot act during the first round of combat. After that, they recover &
join the Initiative order as usual.

18-19 Mute: The PC is rendered unable to speak beyond meaningless gibbering, and the difficulty of CHA tests
is increased by +2.

20 Violent Response: the PC must use their first action in combat to attack the source of their fear using the
maximum fire rate of their weapon, even if the source is only perceived or environmental. The
Complication Range of these attacks is 18-20. The Aim minor action may not be taken.
 MAD-O-METER
Player Characters will accumulate Madness Points over the course of the GM’s campaign, which are tracked
on each character’s Vault-Tec Mad-O-Meter™. These points do not reset at any time, and once certain thresholds are
met on the Mad-O-Meter, the character becomes susceptible to permanent mental afflictions known as Manifestations.

The Mad-O-Meter is organized in increments of 20, from 0 to 100. When a Player Character reaches 20, 40,
60, 80, and 100 Madness Points, they must roll an Intelligence + Survival test (called a Mad-O-Meter Test) with a
difficulty of 2. If they succeed, they do not gain a new Manifestation, but they must reroll the test each time they gain a
new Madness Point. If they fail the Mad-O-Meter Test, they gain a Manifestation, but they do not have to make this
test again until they reach the next threshold on the Mad-O-Meter. When a Manifestation is gained, the player may roll
randomly on the table, or the GM may select a suitable Manifestation. The character may not have duplicate
Manifestations, so rerolls may be necessary.
If the Player Character fails the Mad-O-Meter Test with a Complication, the GM gains 1AP. The character may
not suffer both a Temporary Psychosis and a Manifestation from this roll. However, if the Mad-O-Meter Test is passed
with a Complication, no Manifestation is gained, and the PC may suffer a Temporary Psychosis if the GM chooses.

MANIFESTATION TABLE

Result Manifestation

1-2 Phobia: The PC is afflicted with a phobia of the fear that resulted in this manifestation. All skill tests suffer
an increased complication range of +2 while in proximity of the subject of their phobia.

3-4 Nightmares: The PC suffers nightmares. Each time they attempt to sleep, they must make an
END+Survival test with a difficulty of 1. If they fail, they gain 1 point of Fatigue until they sleep again.

5-6 Trauma: One of the PC’s SPECIAL attributes is reduced by 1, to a minimum of 4. The PC may select the
attribute, or the GM may do so for them.

7-8 Nervous Break: The PC develops a nervous habit of some kind, such as uncontrollable fidgeting or
whispering to themselves. The player or GM may also suggest their own to fit the narrative. If the habit is
mental, all INT tests suffer an increased Complication Range of +1. If the habit is physical, all STR tests
suffer the same penalty.

9-10 Anger: The PC is prone to sudden bursts of anger. The difficulty and Complication Range of all CHA tests
is increased by +1.

11-12 Paranoia: Each time the PC rolls on the fear table, regardless of success or failure, they gain 1 Fatigue
Point.

13-14 Object Attachment: PC develops an obsession with a specific object. If it is taken or lost, they suffer a
complication range of +2 on all skill tests until it is returned or found, and they are likely to obsess over it
even while it is in their possession.

15-16 Homicidal Inclinations: When the PC is engaged in combat, they obsess over the target. At the
beginning of each of their turns in combat, they must roll an END+Survival test with a difficulty of 1. If they
fail, they relentlessly pursue the target until it is killed, and their next turn(s) after it dies must be spent
reaching & brutally maiming the body, if able. Once 1 turn has been spent maiming it, the urge is sated for
7 in-game days.

17-18 Aphasia: The PC loses the ability to speak or write (choose one. flip a coin, GM choice, or player choice)

19-20 Drown the Sorrow: The PC develops a compulsive drinking problem. They become addicted to Alcohol
and cannot be cured. (This effect bypasses any immunity gained from perks. If the PC has a rank in Party
Boy/Girl and they acquire this manifestation, they must choose another perk to replace it.)
 PERKS
The perks included here are designed to interface directly with the Horror system. Their inclusion could help
players mitigate the dangers of long-term psychological damage, especially in games where the GM intends to
incorporate a great deal of horror, so their use is recommended, though not required.

Desensitized
Ranks: 3
Requirements: 5+
Description: At rank 1, you no longer have to make a Madness Test for encounters with a Madness Value of 1. At rank
2, this increases to a Madness Value of 1 or 2. At rank 3, this increases to a Madness Value of 1, 2, or 3. Each time
you take this perk, the level requirement increases by 5.
NOTE: Ranks in this perk are earned for free when Player Characters reach levels 5, 10, and 15, and it does not
prevent them from choosing perks normally at those levels.

Mental Fortitude
Ranks: 1
Requirements: END 6, Mad-O-Meter 20+
Description: When you roll on the Madness Table when encountering a Madness Event, you may reroll 1d20.

Fight or Flight
Ranks: 1
Requirements: AGI 7 or STR 7, Mad-O-Meter 25+
Description: Anytime you gain any Madness Points, you gain 1AP.

Compartmentalization
Ranks: 1
Requirements: Mad-O-Meter 30+
Description: You no longer need to make a skill test to overcome temporary psychoses. They dissipate on their own
after the first scene.
 CURING MADNESS
Can madness be cured? Well… maybe. Let’s consider this particular portion of the supplement optional, for
those GMs who want to be more lenient with their players. Presented below are a few possibilities for mitigating or
eliminating elements of a player’s madness.

1. Therapy - If the GM’s setting has at least one sufficiently well-established settlement, they may opt to include a
psychiatrist NPC who may be contracted to reduce a character’s Mad-O-Meter score. Roll 1CD for every
Madness Point the player wishes to remove. The total result is the number of weeks of consistent therapy
required to reduce the character’s Mad-O-Meter score. The cost is 40 caps per week, and during this time, the
character is unplayable. Following their therapy, they suffer a permanent increase of +1 to the complication
range of Madness Tests.
a. Example: The PC has 23 Madness Points and wishes to reduce it by 12. They roll 12CD for a total of 9.
Their character is unplayable for 9 in-game weeks as they attend regular therapy, and they must pay
360 caps in total for the treatment.

2. Memory Reset - If the GM’s setting contains VR technology, such as what is seen in Fallout 4’s Memory Den,
the character may purchase a memory wipe to remove the bad memories. The character’s Mad-O-Meter score
is reduced in multiples of 20 by this method (for example, if the character’s Mad-O-Meter score is 46, and they
want 2 Manifestations removed, their new score will be 6). The player chooses how many Manifestations to
remove. For each Manifestation removed in this way, the character is reversed 2 character levels, as the
technology is not perfect and other important memories are often removed by accident. The time to accomplish
this is 24 hours per Manifestation, and the price is 250 caps per Manifestation.
a. NOTE: This method may have negative narrative consequences at the GM’s discretion, as certain
events might have been erased from the character’s memory.

3. Medication - While it is virtually impossible to manufacture in the Wasteland, many pre-war pharmaceutical
companies were involved in the creation of antipsychotic medicines. These are hard to find, and their
acquisition would likely be locked behind a quest, but if acquired they could be used to mitigate the effects of
Manifestations. It does not cure Manifestations or Temporary Psychoses, nor does it reduce a character’s
Mad-O-Meter score, but it does provide temporary relief.
a. Antipsychotics: Ignore the effects of all Manifestations. Lasting. Not addictive. Rarity 5. Value 225.
b. Note: This drug cannot be manufactured, but it is affected by the Bio-Comm Mesh armor mod.
 OPTIONAL RULES
● Starting at a higher level
○ Some GMs may wish to begin their campaign at a higher level than 1, or a player may introduce a new
character of higher level part-way through an existing campaign. In either situation, they may allow the
PC to take ranks in the Desensitized perk, to represent an advanced character’s prior experience with
fear-inducing scenarios. If the player opts to do so, they must take 1 Manifestation. Either the player or
the GM may select a Manifestation that suits the character, or they may roll randomly on the
Manifestation table.

● Conversion to a Willpower System

○ If the GM is willing to add a new derived statistic to the game, this method may be a bit more in-depth
and suited to a horror system.
○ A new derived statistic is created: Willpower. A character’s Willpower is equal to the sum of their
Intelligence and Endurance scores. When a Madness Event is encountered, the players roll a quantity
of d20s equal to the Madness Value of the event. For each d20 result that is above their Willpower
Score, their Mad-O-Meter Score increases by 1. If any dice results are 20, the character suffers a
complication, and thus a Temporary Psychosis. Additional complications do not generate additional
psychoses, though they may generate AP for the GM.
○ Players may not spend AP to increase or decrease this pool, though Luck points may be spent to reroll
d20s as usual.

● Horror-Lite
○ Not all tables will be suited to a full-on horror experience. With that in mind, GMs may ignore
Manifestations and the Mad-O-Meter, and focus solely on Temporary Psychoses. The Temporary
Psychosis table is more than enough to sprinkle a bit of suspense and unpredictability into a campaign
without forcing players to risk major, permanent detriments and potential character loss.
○ Another method would be capping the Mad-O-Meter at any arbitrary value the GM decides is fair. This
will allow players to accumulate a few Manifestations without being driven completely insane.
 CREDITS
Hat-tip to my Discord pal Quadee, a long-time Homebrew associate. His experience with horror-based systems
vastly exceeds my own, and his feedback was invaluable to the finalization of this supplement.

This supplement is not endorsed or supported by Modiphius or Bethesda Softworks, and should not be
considered an official expansion of the rules or canon of either Fallout 2d20 or the Fallout universe.