This sparsely populated wilderness seems benign at first glance. A normal patch of terrain, the usual trees, clearings, and rocks. However, perhaps it does seem oddly barren. So you look closer, noticing the signs of ancient battles, the scorched bricks of a shattered mage’s tower or the fallen trees, radiating outward from a central point, where a glowing crater rests. These are all examples of different environmental cataclysms. 

While magic can produce miracles and destruction in equal measure, the power of the cosmos unleashed upon the land can have unintended consequences. In areas of magical corruption, living spells are common, as are mutations and aberrations. Such areas also attract creatures from beyond the mortal world, crossing over where the boundary between the planes is thin.

Where other magical wastelands generate more targeted living spells, areas of environmental cataclysm tend to produce wider area-of-effect creatures, such as that described below.

Living Blight

A miasma rises from the ground, a formless ochre nimbus pulsing with dusky veins of shadow. Where the cloud of energy touches, plants wither and life seems to leach out of the land itself.

This living spell is a cataclysmic version of the blight spell.

Living Blight

Large construct, unaligned
Armor Class 15 (natural armor)
Hit Points 66 (7d10 + 28)
Speed 25 ft., burrow 25 ft., fly 25 ft.

Str	Dex	Con	Wis	Int	Cha
15 (+2)	18 (+4)	18 (+4)	11 (+0)	10 (+0)	6 (−2)

Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities necrotic, poison, radiant
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, poisoned, prone
Senses blindsense 60 ft., tremorsense 30 ft., passive Perception 10
Languages —
Challenge 7 (2,900 XP)

Amorphous. The living spell can move through a space as narrow as 1 inch wide without squeezing.

Magic Resistance. The living spell has advantage on saving throws against spells and other magical effects.

ACTIONS

Multiattack. The living spell makes two Enervating Strike attacks.

Enervating Strike. Melee Spell Attack: +7 to hit, reach 60 ft., one target. Hit: 22 (4d8 + 4) necrotic damage.

Spell Mimicry (Recharge 5–6). The living blight creates a 40-foot-diameter invisible sphere of necrotic energy around itself. When a creature enters the sphere for the first time on a turn, or starts its turn there, it must make a DC 14 Constitution saving throw, taking 22 (5d8) necrotic damage on a failed save or half as much damage on a successful one.

The sphere moves with the living spell and lasts for 10 minutes or until the living spell’s concentration ends (as if concentrating on a spell). The sphere does not function while the living spell is burrowing.

Powered by the Cataclysm

The magic of environmental cataclysms can infuse items with their energies.

Tremorblade, Sword of the Cataclysm

Weapon (any sword), very rare (requires attunement)

This blade seems to tremble slightly when you wield it. You gain a +1 bonus to attack and damage rolls with this magical sword. As an action, you can plunge the tremorblade into the ground, triggering a localized earthquake centered on you. 

Fissures open in the affected area, in a 30-foot radius from you. A total of 1d6 + 1 such fissures open in locations chosen by the GM. Each is 1d10 × 10 feet deep and 10 feet wide, and it extends from one edge of the effect’s area to the opposite edge. A creature standing on a spot where a fissure opens must succeed on a Dexterity saving throw or fall in. A creature that successfully saves moves with the fissure’s edge as it opens.

A fissure that opens beneath a structure causes it to automatically collapse (see the earthquake spell). Once you use this feature, you must finish a long rest before using it again.

In Midgard: The White Mountain Marches

Apart from the Western Wastes, the White Mountain Marches are the best-known environmental cataclysm. Once the common battlefield between the legions of the Mharoti Empire and now-fallen Illyria, the marches are saturated with spell residue, dragon’s blood, alchemical weapons, and spilled potions. Today, only a scattering of goat-herding villages and heavily guarded mining settlements remain aboveground. Below, however, is another story. The magic-hating ghostfolk (see grey orcs in Tome of Beasts 2) dwell underground and surface to snuff out magic users or monsters with equal fury.

Story Seed: Descent into the Depths

Hired by a wealthy acquaintance or the representative of a prominent university, the PCs venture into the Marches, or another area of environmental cataclysm, on the trail of a missing research expedition. Professor Marcello and three of his students failed to arrive at the nearest settlement and the worst is feared. Venturing into the corrupted wilderness, the PCs discover the professor’s broken wagon, guarded by a living blight. Defeating the construct, the PCs find evidence pointing toward a nearby barrow where the professor searches for a tremorblade once wielded by an ancient warlord. However, the locals, both above and below the ground, do not take kindly to grave robbers.

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