Rare Monsters for Random Encounters (5e Variant Rule)

Rare Monsters for Random Encounters

Rare monsters are monsters that have been enhanced with special bonus properties or mutations in addition to their normal attacks. These properties, known as "Rare Affixes", grant monsters a wide variety of elemental damage effects, as well as things like regenerative auras, improved defenses, flight, and much more. Rare monsters can be inserted into any 5e game to spice up random encounters in a quick-and-dirty fashion, and to catch complacent adventurers off-guard in the process.

Whenever an adventuring party triggers a random encounter, the DM can choose to roll another d20. On a natural 20, the DM may choose one monster in the random encounter to become a Rare Monster, and must then roll another d20 to determine which Rare Affix this monster possesses. Each Rare Affix attached to a monster adds +2 to its hit dice, and will increase its Challenge Rating by one level (ex. CR 1/4 increases to CR 1/2, CR 1 increases to CR 2, etc....). The DM can even give rare monsters exciting names if they so wish, to further cement their special status.

Affixes for Rare Monsters d20 Rare Affix Affix Description 1 Corrosive Acid resistance plus bonus acid damage to attacks (equal to half the damage dice of each weapon attack). Any pre-existing elemental properties to weapon or spell attacks are replaced with acid. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into acid damage. If the monster already had resistance, it now has immunity to acid damage instead. A small or larger corrosive monster can use its action to exhale a line of acid (15 ft. for small & medium size, 30 ft. for large size, 60 ft. for huge size, 90 ft. for gargantuan size). Each creature in that line must make a Dexterity saving throw (equal to 8 + proficiency + CON mod of the monster), taking acid damage on a failed save (1d6 at CR 1/2 and lower, 2d6 at CR 1-5, 3d6 at CR 6-10, 4d6 at CR 11-15, 5d6 at CR 16+), or half as much on a successful one. This ability has a recharge of 5-6. 2 Frozen Cold resistance plus bonus cold damage to attacks (equal to half the damage dice of each weapon attack), as well as vulnerability to fire damage. Any pre-existing elemental properties to weapon or spell attacks are replaced with cold. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into cold damage. If the monster already had resistance, it now has immunity to cold damage instead. A creature struck by this monster's weapon attacks is slowed by 10 feet until the start of its next turn. 3 Burning Fire resistance plus bonus fire damage to attacks (equal to half the damage dice of each weapon attack), as well as vulnerability to cold damage. Any pre-existing elemental properties to weapon or spell attacks are replaced with fire. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into fire damage. If the monster already had resistance, it now has immunity to fire damage instead. When this monster dies, it explodes in a burst of fire. Each creature within 10 feet of it must make a Dexterity saving throw (save DC equals 8 + proficiency + CON mod of the monster), taking fire damage on a failed save (1d6 at tiny & small size, 2d6 at medium size, 3d6 at large size, 4d6 at huge size, 5d6 at gargantuan size), or half as much on a successful one. Flammable objects that aren't being worn or carried in that area are ignited. 4 Arcane Force resistance plus bonus force damage to attacks (equal to half the damage dice of each weapon attack). Any pre-existing elemental properties to weapon or spell attacks are replaced with force. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into force damage. If the monster already had resistance, it now has immunity to force damage instead. This monster also has Magic Resistance, and its weapon attacks are considered magical, unless either of these two traits already applied without the affix. 5 Voltaic Lightning resistance plus bonus lightning damage to attacks (equal to half the damage dice of each weapon attack). Any pre-existing elemental properties to weapon or spell attacks are replaced with lightning. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into lightning damage. If the monster already had resistance, it now has immunity to lightning damage instead. A creature that touches this monster or hits it with a melee attack while within 5 feet of it takes 3 (1d6) lightning damage. 6 Necrotic Necrotic resistance plus bonus necrotic damage to attacks (equal to half the damage dice of each weapon attack), as well as vulnerability to radiant damage. Any pre-existing elemental properties to weapon or spell attacks are replaced with necrotic. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into necrotic damage. If the monster already had resistance, it now has immunity to necrotic damage instead. This monster regains hit points equal to half the amount of damage it inflicts with weapon attacks. Every successful attack from this monster leaves a stacking -1 debuff to all healing and temporary hit points received for 1 minute. 7 Toxic Poison resistance plus bonus poison damage to attacks (equal to half the damage dice of each weapon attack), and cannot be poisoned. Any pre-existing elemental properties to weapon or spell attacks are replaced with poison. If the monster already had resistance, it now has immunity to poison damage instead. This monster also gains the Fetid Cloud ability, and can use it once per day (save DC equals 8 + proficiency + CON mod of the monster). 8 Psychokinetic Psychic resistance plus bonus psychic damage to attacks (equal to half the damage dice of each weapon attack). Any pre-existing elemental properties to weapon or spell attacks are replaced with psychic. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into psychic damage. If the monster already had resistance, it now has immunity to psychic damage instead. This monster can use its action to emit a psychic scream. Each creature of the monster's choice within 15 feet of it must must succeed on a Wisdom saving throw (save DC equals 8 + proficiency + CHA mod of the monster) or become frightened for 1 minute. This ability has a recharge of 5-6. 9 Radiant Radiant resistance plus bonus radiant damage to attacks (equal to half the damage dice of each weapon attack), as well as vulnerability to necrotic damage. Any pre-existing elemental properties to weapon or spell attacks are replaced with radiant. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into radiant damage. If the monster already had resistance, it now has immunity to radiant damage instead. This monster sheds bright light in a 10-foot radius and dim light for another 10 feet. This monster can use its action to target one creature it can see within 30 feet of it. If the target can see it, the target must succeed on a Constitution saving throw (save DC equals 8 + proficiency + CON mod of the monster) or be blinded for 1 minute. This ability has a recharge of 5-6. 10 Sonic Thunder resistance plus bonus thunder damage to attacks (equal to half the damage dice of each weapon attack). Any pre-existing elemental properties to weapon or spell attacks are replaced with thunder. If any weapon or spell attacks normally inflict poison damage, convert half the damage dice of that poison damage into thunder damage. If the monster already had resistance, it now has immunity to thunder damage instead. This monster can use its action to emit a blast of thunderous force. Each creature within a 15-foot radius must make a Constitution saving throw (save DC equals 8 + proficiency + CON mod of the monster). On a failed save, a creature takes 2d8 thunder damage and is pushed 10 feet away from the monster. 11 Stone-skinned This monster's minimum AC is 17, and it is resistant to all bludgeoning, piercing, and slashing damage from nonmagical weapons that aren't made from adamantine, but gains a vulnerability to thunder damage. No change to AC if it was already higher than 17. This monster also moves 5 feet slower due to its increased weight. 12 Flying This monster is capable of flight through whatever means the DM feels is justified for the original monster. It gains a flight speed equal to its fastest movement speed. If the original monster already had flight, reroll this d20 result. 13 Bolstering When this monster dies, its death cry empowers all allied creatures within 15 feet of it, granting them the effects of 5e SRD:Bless and 5e SRD:False Life for 1 minute. 14 Raging This monster goes berserk once it reaches half of its maximum hit points for 1 minute. While this monster is raging, it gains resistance to bludgeoning, piercing, and slashing damage, advantage on melee weapon attack rolls, and a bonus to all damage rolls (+1 for CR 1/4 to 4, +2 for CR 5-10, +3 to CR 11-16, +4 to CR 17+). While enraged, all attack rolls against this monster also have advantage. 15 Sanguine When this monster dies, it leaves a pool of tainted blood on the ground in a 10-foot radius from its point of origin for 1 minute. Allied creatures that move into this area, or start their turn in it, regain 1d8 hit points. Enemy creatures who move into this area, or start their turn in it, take 4 (1d8) poison damage. 16 Nature-touched This monster permanently gains the effects of 5e SRD:Barkskin, as well as the effects of either aura of life, aura of purity, or aura of vitality (chosen by the DM). 17 Many-armed This monster has an extra pair of arms, and gains a multiattack feature if it did not already have it. If the monster already has multiattack, it instead gains one additional weapon attack. 18 Crystalline This monster's minimum AC is 18, and it is immune to all bludgeoning, piercing, and slashing damage from nonmagical weapons that aren't made from adamantine. No change to AC if it was already higher than 18. This monster also moves 5 feet slower due to its increased weight. 19 Prismatic This monster becomes immune to acid, cold, fire, lightning, and poison damage, gains Magic Resistance and Immutable Form, and cannot be blinded, petrified, or poisoned. Its weapon attacks also become magical. Whenever this monster is subjected to acid, cold, fire, lightning, or poison damage, it regains a number of hit points equal to the elemental damage dealt. 20 Champion This monster gains two Rare Affixes instead of one. Roll two d20s for this table, and reroll any die with a value of 20. If both the "Stone-skinned" and "Crystalline" affixes are rolled at the same time, you may only keep one, and must reroll the other die. This also applies if you roll both "Frozen" and "Burning", or if you roll both "Necrotic" and "Radiant". Legal Champion Affix Combinations (WIP) Corrosive Corrosive + Frozen = Acidfrost Corrosive + Burning = Magmic Corrosive + Arcane = Acidomantic Corrosive + Voltaic = Shock-melting Corrosive + Necrotic = Death-oozing Corrosive + Toxic = Irradiated Corrosive + Psychokinetic = Acidokinetic Corrosive + Radiant = Acidlight Corrosive + Sonic = Sound-melting Corrosive + Stone-skinned = Acid-stone Corrosive + Flying = Sky-melting Corrosive + Bolstering = Acid-bolstering Corrosive + Raging = Acid-raging Corrosive + Sanguine = Blood-melting Corrosive + Nature-touched = Acidflower Corrosive + Many-armed = Corrosion-armed Corrosive + Crystalline = Onyx Corrosive + Prismatic = Acid-Prism (To be continued......) Frozen Frozen + Arcane = Cryomantic Frozen + Voltaic = Frost-shocked Frozen + Necrotic = Blackfrost Frozen + Toxic = Poisonfrost Frozen + Psychokinetic = Cryokinetic Frozen + Radiant = Coldlight Frozen + Sonic = Thunderfrost Frozen + Stone-skinned = Stone-frozen Frozen + Flying = Skyfrost Frozen + Bolstering = Frost-bolstering Frozen + Raging = Ice-raging Frozen + Sanguine = Blood-frost Frozen + Nature-touched = Frostflower Frozen + Many-armed = Frozen-armed Frozen + Crystalline = Diamond Frozen + Prismatic = Frost-prism Burning Burning + Arcane = Pyromantic Burning + Voltaic = Flame-shocked Burning + Necrotic = Blackflame Burning + Toxic = Poisonflame Burning + Psychokinetic = Pyrokinetic Burning + Radiant = Firelight Burning + Sonic = Thunderfire Burning + Stone-skinned = Blackrock Burning + Flying = Skyfire Burning + Bolsterting = Flame-bolstering Burning + Raging = Fire-raging Burning + Sanguine = Bloodfire Burning + Nature-touched = Fireflower Burning + Many-armed = Fire-armed Burning + Crystalline = Ruby Burning + Prismatic = Flame-prism Arcane Arcane + Voltaic = Electromantic Arcane + Necrotic = Necromantic Arcane + Toxic = Venomantic Arcane + Psi-terror = Psychomantic Arcane + Radiant = Photomantic Arcane + Sonic = Audiomantic Arcane + Stone-skinned = Geomantic Arcane + Flying = Aeromantic Arcane + Bolstering = Arcana-bolstering Arcane + Raging = Spell-raging Arcane + Sanguine = Sanguimantic Arcane + Nature-touched = Arcanaflower Arcane + Many-armed = Force-armed Arcane + Crystalline = Moonstone Arcane + Prismatic = Spectrumantic 0.00 (0 votes) Back to Main Page → 5e Homebrew → Rules