Monsters usually encountered in space (those with a speed listed as Spacefaring Slow, Spacefaring Average, or Spacefaring Fast) are typically more powerful than terrestrial monsters of the same challenge rating. These cosmic threats are strong enough to match a party’s ship, not merely the party itself.

Spacefaring monsters of CR 3 and below have similar statistics to standard (non-spacefaring) monsters. For a battle in which a party must face a CR 4 or higher spacefaring monster without the benefit of a starship, triple the spacefaring monster’s XP and treat it as 3 standard monsters of its Challenge Rating for purposes of encounter building. For a battle in which a starship battles a CR 4 or higher standard monster, grant ⅓ of the monster’s XP and treat it as a monster of ⅓ its CR for the purposes of encounter building.

The world can be a dangerous place and the environment might pose a deadly threat all by itself. In addition to their inherent danger, encounter elements offer ways to enhance the perils of exploration challenges or combat to make both more satisfying. A duel atop a bridge or traversing a narrow crossing is all the more exciting when deadly lava runs below rather than rushing water, and a hallway fight or dungeon trap with a plethora of green slime is a different kind of challenge altogether!

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Challenge Rating Increase

The challenge rating of a combat encounter or exploration challenge can be increased when an encounter element is included so long as it poses an active threat—a cage match near a volcanic pit is more dramatic, but no more dangerous than usual.

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Bombarded (+2)

An area which is under constant bombardment from artillery or starship fire can be very hazardous.

Loud Noise. Creatures within the area participants can only hear sounds within 15 feet of them (except for loud, explosive noises).

World Actions

Artillery. Each creature in the area makes a DC 10 Dexterity saving throw or they take 4d6 bludgeoning damage.

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Irradiated (+2)

Deadly radiation fills the air, threatening the lives of all who brave exposure.

Every five minutes a creature spends in an irradiated area it must make a DC 15 Constitution saving throw . On a failure, the creature contracts radiation sickness (see Maladies on page 281).

Creatures immune to poison damage, or who are wearing radiation shielded clothing, are not affected by irradiated areas.

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Irradiated, Severe (+4)

Nuclear meltdowns, quasars, and breached antimatter engines create even more intense radiation.

Creatures immune to poison damage, or who are wearing radiation shielded clothing, treat severely irradiated areas as irradiated areas.

World Actions

Radiation Poisoning. A creature which begins its turn in a severely irradiated area must make a DC 15 Constitution saving throw . On a failure, the creature takes 28 (8d8) poison damage and is poisoned until medically treated using an anti-rad drug or similar effect. Additionally, the creature contracts radiation sickness .

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High Gravity (+2)

The ranges of ranged weapons are halved, as are all jump distances. When a creature makes its first attack in a round using a weapon that does not have the dual-wielding property, it makes a DC 12 Athletics check or subtracts 1d4 from its attack rolls for 1 round. Falling damage is treated as twice the distance in the area and there is no maximum amount of damage that can be taken from a fall. For every hour spent in the area, a creature not acclimated to it makes a Constitution saving throw (DC 8 + the number of hours spent in the area) or gain a level of fatigue (maximum 4 levels of fatigue).

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Low Gravity (-1)

The ranges of ranged weapons are doubled, as are all jump distances. Falling damage is treated as half the distance in the area. In addition, damage from bludgeoning weapons is reduced by half.

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Zero Gravity (+1)

While artificial gravity is a staple of most sci-fi settings, many settings stick to a more realistic depiction of weightless movement, using the environment around them as useful handholds and points to kick off from.

Creatures treat zero-G environments as difficult terrain so long as they are adjacent to a solid surface. Creatures may move into areas without an adjacent surface in this way, but if they end their turn with no adjacent surface they begin drifting and their movement speed is reduced to 0. Drifting creatures can throw any item on their person that weighs at least 5 pounds or use any propellant item (such as a cytospray, construction foam, spray adhesive, spray paint, or zero-friction lubricant) to move up to 10 feet as a bonus action.

Spacesuits. Creatures with the spacefaring feature or creatures wearing armor with the spacefaring feature ignore the difficult terrain caused by zero-G environments and are immune to drifting. Creatures with a natural climb speed also ignore the difficult terrain caused by zero-G environments, but are not immune to drifting.

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Thick/Thin Atmosphere (+1)

While both thick and thin atmospheres are very dissimilar, their effects on creatures are not so different. Creatures can breathe in these atmospheres, but it is harder. Every hour, a creature in a thick or thin atmosphere must make a DC 12 Constitution saving throw or gain one level of fatigue .

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Vacuum (+2)

An area of vacuum has no air, so creatures that need to breathe must use another source of air or begin to suffocate once they cannot hold their breath. In addition, the area carries no sound, so hearing-based checks made to perceive automatically fail.

Spacesuits. Armor with the spacefaring classification protects its wearer from hard vacuum, but even the smallest puncture in a suit can be deadly. As such, most spacefaring suits are equipped with self-sealing technology to protect against small punctures, tears, and fractures, but a critical hit renders a spacefaring suit damaged. When a creature’s spacefaring suit is damaged, roll 1d6 at the start of each of the creature’s turns. On a roll of 6 the suit is no longer able to provide protection from hard vacuum. A second critical hit before the damage is patched or repaired completely breaks the suit, rendering it broken and ineffective.

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Vacuum Breach (+3)

When there is a pressure differential between two areas, such as a hull breach or an open door leading to the surface of an airless rock, the atmosphere rushes out in an attempt to level out the differential. This takes the form of a rushing wind.

Ranged weapon attacks and Perception checks that rely on hearing have disadvantage in high winds. In addition, the rushing air extinguishes any open flames, disperses fogs and smoke, and forces any flying creature to land before the end of its turn or fall.

World Actions

Rushing Winds. Each creature in the area must make a DC 14 Strength saving throw or be pulled 20 feet in the direction of the winds. A creature with one or more spare limbs (at the Narrator’s discretion) may use a bonus action to grab on or anchor itself, which allows it to make the saving throw with advantage .

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Hard Vacuum & Lingering Injuries

The vacuum of space is also utterly chilling or scorching hot, depending on whether a creature is in sunlight or shadow. The vacuum deals 11 (3d6) cold or fire damage to a creature at the start of each of its turns in the area. If cold damage (but not fire damage) from a vacuum drops a creature to 0 hit points or happens after they are already at 0 hit points, they suffer a lingering injury. The Narrator can dictate an injury and its effects or determine it by rolling a d4: 1—blindness, 2—burns, 3—loss of taste, 4—frostbite (see Table: Frostbite).

1d4	Frostbite
1	Finger: –2 Penalty to Sleight of Hand checks.
2	Nose: –2 Penalty to Perception checks that rely on scent.
3	Ear: –2 Penalty to Perception checks that rely on hearing.
4	Toe: Base walking speed is reduced by 5 feet.

After a day of rest, the affected creature may make a DC15 Constitution saving throw , made with advantage if it has received medical attention since the exposure. On a success, the creature heals; on a failure, the affliction persists. The creature may make further Constitution saving throws after each subsequent day, but the DC increases by 1. If the creature fails three of these saves, the injury becomes permanent.

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Zirkon Crystals (+2)

Zirkon is a rare natural crystal which dampens psionic energy. The cost to manifest psionic powers in an area containing zirkon crystals is doubled. Additionally, psionic powers of level III or less cannot penetrate solid zirkon barriers (see Objects).
 

While medical advances make many common health hazards inconsequential, some maladies still present a threat to voidrunners who are unlucky enough to suffer them.

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Treating a diseased creature over the course of a short rest with a successful Medicine check (tier 1: DC 10, tier 2: DC 14, tier 3: DC 18, tier 4: DC 22) grants advantage on its next saving throw against the disease.

Severe diseases. The diseases below are presented in their most common form. Sometimes a more severe version of a disease is encountered. These diseases are considered one tier higher, and all saving throws made against the disease are made at disadvantage .

Mental stress effects. Some maladies inflict a short or long-term mental stress effect (see Appendix A of the Adventurer’s Guide). The duration of these effects is noted in the malady’s description.

Fatigue and strife. Some maladies either inflict levels of fatigue or strife , or they prevent the victim from recovering levels of fatigue or strife, even if they are able to rest at a haven.

Recovery. Each malady describes the ways in which a victim might recover. Typically this requires three successful consecutive saving throws.

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Apoplectic Psychosis (Tier 2)

This disorder affects the emotional regulation of the brain, resulting in extreme anger and aggression. Victims are provoked to outburst of rage by insignificant triggers, often resulting in violence.

A creature which contracts apoplectic psychosis gains the enraged condition. Additionally, they suffer from the enraged mental stress effect.

Recovery. The victim makes a DC 15 Wisdom saving throw after each long rest. After three consecutive successful saving throws, the victim recovers.

Brainpox (Tier 3)

This virus affects the brain and nerve centers of its victim. It is often caught via physical contact, especially via the eyes or nose. The victim begins to lose their senses of sight and hearing, with paralysis being the end result.

At the end of each week, the victim must make a DC 15 Constitution saving throw . After the first failure, the victim gains the blinded condition. After the second failure, they gain the deafened condition. After the third failure, the victim gains the paralyzed condition and stops making weekly saving throws.

Recovery. On a successful weekly saving throw, the victim loses the most recent of those three conditions which it gained via this malady. Once they have made a successful saving throw while not suffering from one of the conditions, they recover.

Victims which have reached the paralysis stage of this malady do not recover naturally. However, a DC 21 Medicine check performed by a practitioner who keeps the victim under their care for a full week removes the paralyzed condition and allows the victim to resume making weekly saving throws.

Cellular Shingles (Tier 2)

This painful viral infection, affects the victim at a cellular level. While it is not life-threatening, it is intensely painful. The victim develops rashes and blisters all over their body, and becomes very sensitive to bright lights.

A creature which has contracted cellular shingles gains the agonized condition.

Recovery. The victim makes a DC 15 Constitution saving throw after each long rest. After three consecutive successful Constitution saving throws, the victim recovers.

Orman’s Syndrome (Tier 2)

This illness attacks the neural structures of the brain, gradually causing memory loss. By the time it reaches its conclusion, the victim loses all sense of identity and all long-term memories. The victim will not recognize close friends or family members, or recall their own name, career, or skills.

At the end of each long rest, the victim must make a DC 15 Wisdom saving throw . On a failure, their Wisdom score is reduced by 1 point and they spend that day suffering from the amnesiac condition.

A creature whose Wisdom is reduced to zero suffers complete, permanent amnesia.

Recovery. After three consecutive successful Wisdom saving throws, the victim recovers and their Wisdom score returns to its normal value.

Macrovirus (Tier 1)

This airborne illness is particularly dangerous because it reduces the victim’s desire to actually do anything about it. The illness causes extreme lethargy, worsening to the point where the victim will not eat, and simply wastes away.

A creature which has contracted macrovirus cannot recover fatigue during a long rest, even if they are in a haven.

Recovery. Creatures with macrovirus do not recover on their own. However, it can be treated with daily DC 12 Medicine checks, with the victim recovering after three consecutive successful checks.

Psionic Evervation Syndrome (Tier 2)

This malady only affects creatures with psionic ability. After every long rest, the creature makes a DC 15 saving throw using its psionic ability score. On a failed saving throw, the creature’s maximum psionic points are reduced by 1 point.

Recovery. After three consecutive successful saving throws, the victim recovers. Their psionic pool recovers by 1 point per long rest until it has been restored to its normal value.

Psychic Melancholia (Tier 2)

This malady plunges the victim into a rapid, increasing spiral of depression. After each long rest, the victim must make a DC 12 Wisdom saving throw . On a failed save, the victim gains one level of strife .

A creature which has contracted psychic melancholia cannot recover strife during a long rest, even if they are in a haven.

Recovery. After three consecutive successful Wisdom saving throws, the victim recovers.

Radiation Sickness (Tier 2)

Radiation is deadly, and those exposed to it risk contracting radiation sickness. Symptoms include vomiting, intestinal pain, bleeding, hair loss, and fever.

A creature with radiation sickness is poisoned . Additionally, at the end of each long rest, the creature must make a DC 15 Constitution saving throw or their hit die maximum is reduced by 1 die. A creature whose hit die maximum is reduced to zero hit dice dies.

Recovery. Left alone, radiation sickness will result in death. However, it can be treated with daily DC 15 Medicine checks, with the victim recovering after three consecutive successful checks. The checks are made at advantage if anti-rad drugs are available (see Chapter 3: Equipment).

RAR-1 (Tier 3)

This frightening malady, Rapid Aging Retrovirus, causes its victims to age rapidly. It is believed that this malady is an artificially created bioweapon, but its specific origins are unknown.

A creature which has contracted RAR-1 ages one year during each long rest. For every 5 years in which the creature ages in this manner, its Strength, Dexterity, and Constitution ability scores are reduced by 1 point. When any of these scores reaches zero, the victim dies of old age.

Recovery. Creatures with RAR-1 do not recover on their own. However, it can be treated with weekly DC 21 Medicine checks, curing the victim after three successful checks. However, the victim does not recover the lost years, and remains at the biological age it reaches before it was cured. The victim recovers half (round up) of any lost ability score points.

 

Rigellian Fever (Tier 1)

This powerful virus causes extreme fever, sweating, and nausea, eventually resulting in the victim’s death. At the end of each long rest, the victim must make a DC 12 Constitution saving throw or suffer a level of fatigue .

Recovery. After three consecutive successful Constitution saving throws, the victim recovers.

Salt Plague (Tier 1)

This unpleasant disease feeds on the victim’s salt levels. The victim eventually loses their humanity as their salt cravings become so intense that they become violent, seeking the salty blood of other victims. This malady has many things in common with legends of vampirism.

A creature which has contracted salt plague suffers intense fatigue if it does not consume sufficient salt. It can draw salt from the blood of other living creatures, making an unarmed attack roll, and dealing 1d4 piercing damage on a hit. Each day, the creature must successfully drain salt three times from one or more living creatures or gain one level of fatigue .

Normal salt deposits, or even table salt, can help to alleviate the cravings. A creature with salt plague which consumes regular salt can make a DC 10 Wisdom saving throw. On a success that dose of salt counts as one of their three required doses per day. On a failure, the salt has no effect. A creature can only attempt to alleviate cravings in this way three times per day.

Recovery. The only cure for salt plague is isolation. After 7 days with no intake of salt, the victim is cured of the malady–if they survive the process.

Space Dementia (Tier 1)

Space dementia affects a small number of space travelers when they first encounter FTL speeds. It can be treated, but left alone it will result in hallucinations, and madness.

After each long rest , the victim must make a DC 12 Wisdom saving throw . On a failed saving throw, the victim suffers a randomly determined short-term mental stress effect (see Trials & Treasures) until their next long rest.

Recovery. Space dementia is usually temporary. The victim recovers after a single successful Wisdom saving throw.

Space Ennui (Tier 1)

The void affects different people in different ways. Space ennui degrades the victim’s emotional centers, causing depression, weariness, and apathy. The victim simply stops caring about things, including their own interests, hobbies, friends, family, and even food.

At the end of each long rest , the victim must make a DC 12 Wisdom saving throw . On a failure, they spend that day suffering from the placid condition. Medical treatment cannot assist with these saving throws, and the victim does not make the saving throws at advantage as normal when under medical care.

A creature which has contracted space ennui cannot recover strife during a long rest, even if they are in a haven.

Recovery. After three consecutive successful Wisdom saving throws, the victim recovers.

The universe is a wondrous place and across their journeys the voidrunners are bound to see some things that are interesting or extraordinary yet pose no threat or danger. Narrators can use this scenery to heighten the sense of adventure and mystery, introduce new quests, or tweak them to help guide a wayward party back to an important task they’ve left unfinished.

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Travel Scenery (d100)

1 An ancient monolith, smooth and black like marble. It seems impervious to all damage.

2 A copse of bioluminescent trees, whose colors change in response to sounds.

3 A swarm of luminescent insects which swirls in mesmerizing, colorful patterns.

4 A geothermal spring with water that changes color based on the temperature.

5 Melodic winds which whisper through the surrounding scenery, creating eerie but beautiful music.

6 A field being farmed by a group of autonomous farming robots.

7 A large digital billboard projecting advertisements and news. It informs the voidrunners of something of interest to them.

8 A column of automated taxis moving slowly along the road.

9 A holographic street performer, juggling fire.

10 A holo-pet–a dog, cat, or small alien.

11 An interactive wall mural featuring street art which changes constantly.

12 Unusual looking graffiti showing some kind of symbol.

13 A crashed starship. It looks like it’s been there for years, now overgrown with vegetation.

14 A crashed starship. There’s still smoke–it crashed recently.

15 An amphitheater carved into a mountainside, designed with perfect acoustics. When the wind blows through it, faint echoes of ancient performances can be heard.

16 A ruined observatory with a large, damaged telescope and star maps etched into the walls. It shows a sophisticated understanding of astronomy.

17 A circular arrangement of colossal stone pillars, each inscribed with unknown symbols and positioned to align with specific astronomical events.

18 Large earthen mounds containing tombs of ancient alien leaders, covered with hieroglyphics depicting their lives and achievements.

19 Large stones covered with glowing runes scattered across the landscape, possibly used as markers or for mystical purposes by the ancient civilization.

20 Stunning auroras caused by the planet’s strong magnetic field, with vibrant colors and dynamic shapes that dance across the sky, visible even during the day.

21 Fog that emits a soft, ambient glow, creating an otherworldly atmosphere. This phenomenon often occurs in areas with high concentrations of bioluminescent microorganisms.

22 Rain that crystallizes upon contact with the ground, forming beautiful, intricate patterns of crystalline structures that shimmer in the light.

23 A waterfall that is perpetually frozen in time, with ice that glows softly from within due to unique mineral properties.

24 Rocks that slowly move and grow over time, sometimes forming new shapes or merging with others, suggesting a form of geological life.

25 A large swathe of land blackened and charred from intense heat or energy weapons, with the remnants of structures and vehicles scattered throughout.

26 Wreckages of advanced starships and fighter craft littering the ground, some still smoldering or emitting faint signals, indicating recent aerial battles.

27 Extensive networks of trenches and fortifications, hastily dug and now deserted, filled with discarded equipment and supplies.

28 A small settlement reduced to ruins, with homes and buildings partially collapsed or burnt, showing signs of hasty evacuation and fierce fighting.

29 Open fields dotted with large craters from explosions, with debris and fragments of weapons or armor scattered around, testifying to intense bombardment.

30 An area where all electronic devices and vehicles are non-functional, affected by recent electromagnetic pulse attacks, leaving machinery and robots frozen in place.

31 Monuments and statues defaced or destroyed in a conflict, symbolizing both cultural loss and the rage of warfare.

32 Streets and paths blocked by hastily constructed barricades made from debris, vehicles, and whatever materials were available, indicating desperate defensive efforts.

33 Sculptures that seem to defy gravity, hovering in the air or balanced on impossibly small points of contact, creating a sense of wonder and disbelief.

34 A small urban oasis with plants genetically modified to thrive in the city environment, featuring unique colors and patterns that stand out amidst the concrete jungle.

35 The body of a giant, hundred-foot tall robot, overgrown with weeds.

36 A flock of alien-looking birds with bright colors wheeling in the air.

37 A tree decorated with the skulls of some kind of alien species.

38 Distant flashes and booms, the signs of a far-off conflict.

39 Flashes of light in the sky, the signs of an orbital conflict.

40 A seemingly bottomless pit.

41 A meticulously cultivated garden full of exotic alien plants.

42 A mysterious metal archway; it was clearly once a technological device but it no longer works.

43 A petrified forest, where all the trees are made of stone.

44 A distant spire stretching impossibly high into the sky.

45 Fragments of pottery, tools, or sculptures from a long-lost civilization.

46 Small chunks of rock from space, possibly containing rare minerals or elements. They have a charred exterior and a metallic sheen.

47 Small, cylindrical devices are scattered on the ground. They could contain maps, logs, or messages from the planet’s inhabitants or visitors.

48 The remains of alien mollusks or crustaceans, with shells that have intricate patterns and iridescent surfaces.

49 Large, flat leaves with glowing veins running through them. These leaves might have medicinal properties or be used in local cuisine or rituals.

50 A shimmering, multifaceted natural crystal structure.

51 Small, discarded playthings from an alien culture, possibly resembling animals, vehicles, or abstract shapes.

52 The discarded exoskeletons of giant alien insects, with intricate patterns and durable, chitinous structures.

53 An energy vortex swirling high in the atmosphere.

54 An abandoned alien market with stalls and remnants of various goods.

55 Strange metallic orbs that float a few inches above the ground and emit a faint hum.

56 An ancient sundial that aligns with multiple celestial bodies.

57 A small, portable shrine with offerings from an unknown religion.

58 A collection of bones from various alien species, arranged in a deliberate pattern.

59 Alien fruit that emits a sweet fragrance and glows faintly.

60 Fragments of an alien flag or banner, tattered and faded.

61 A grove of trees with bark that resembles polished metal.

62 A cluster of alien eggs, some of which are beginning to hatch.

63 An alien painting depicting a scene from the planet’s history.

64 An old, rusted machine partially buried in the ground.

65 Alien hieroglyphs etched into the rock face of a cliff.

66 Alien fossils embedded in a rock formation.

67 A stone well filled with a shimmering, unknown liquid.

68 An ancient alien tomb, half-buried and overgrown with vegetation.

69 A large metallic sphere, about 4 feet across, perfectly smooth. It’s function is unknown.

70 A patch of flowers that open and close in response to nearby movement.

71 An expensive, luxurious space yacht guarded by a sole robot.

72 A solar flare which causes wondrous aurora in the sky.

73 An intense plasma storm with lightning bolts which illuminate the sky.

74 Rain made of tiny crystalline particles which shimmer as they fall, refracting light into dazzling rainbows.

75 A temporal thunderstorm which disorients travelers with brief time skips and moments of slow-motion.

76 Electrically charged hailstones which spark and crackle as they fall.

77 A shooting star which grows quickly closer, crashing to the ground as a meteorite nearby.

78 A dense fog imbued with a bright, unusual color.

79 The burned-out remains of a robot, its circuits clearly fried, blaster fire scorching its body.

80 A smoking crater, hundreds of feet across. What could have crashed here?

81 An errant automated piece of farm machinery, wandering on its own down the road.

82 A malfunctioning combat drone hovering 5 feet in the air, sparks shooting from its damaged body.

83 An area of ground which has been superheated and now resembles glass.

84 A giant symbol scorched into the ground across the width of a large field.

85 A small, robotic chicken.

86 A holographic message on loop, repeating a warning over and over.

87 An empty escape pod.

88 An escape pod containing a small child, perhaps two years old.

89 A corpse with a visible blaster burn in its chest.

90 A half-dozen spotlights in the distance, probing the sky.

91 A crudely made sign with a helmet atop it, the words ‘Keep Away” spray painted on to it.

92 A herd of large alien bovines wandering across the landscape.

93 A bonfire upon which has been thrown the armor of a number of soldiers.

94 The skeleton of a void dragon, hundreds of feet long.

95 A graveyard, with 24 unnamed graves lined neatly in 4 rows of 6.

96 A 30-foot long tusk.

97 A probe. It has been blasted, and lies broken on the ground. Its origins are mysterious.

98 An ancient stone bridge, full of holes. The holes have been replaced by glowing forcefields.

99 A series of interconnected, shimmering pools that contain the collective memories of the planet’s inhabitants. When touched, the water reveals glimpses of the past.

100 A vast, bioluminescent botanical garden where every plant and tree glows with a different color, creating a breathtaking, everchanging landscape of light and shadow.