Rooted Colossus. The Corrupted Soul Mangrove cannot be knocked prone or moved against its will.
Swampbound Awareness. The Corrupted Soul Mangrove knows the location of any creature in contact with water or mud within 60 feet of it.
Labyrinth Lung (Corrupted). The Corrupted Soul Mangrove constantly emits a cloud of toxic spores in a 30-foot radius. The area is lightly obscured. A creature that starts its turn in the area must succeed on a DC 15 Constitution saving throw or take 9 (2d8) poison damage and be poisoned until the end of its next turn. On a successful save, the creature takes half as much damage and is not poisoned.
Mythic Trait: Heart of Rot. If the Corrupted Soul Mangrove is reduced to 0 hit points, it does not die or fall. Instead, its trunk splits open, and a Chuul emerges in an unoccupied space within 10 feet of it. The Chuul acts immediately after the Corrupted Soul Mangrove in the initiative order. When the Chuul is reduced to 0 hit points, both it and the Corrupted Soul Mangrove die.
Multiattack. The Corrupted Soul Mangrove makes three Root Slam attacks.
Root Slam. Melee Weapon Attack: +9 to hit, reach 20 ft., one target. Hit: 16 (2d10 + 5) bludgeoning damage. If the target is a Large or smaller creature, it must succeed on a DC 15 Strength saving throw or be grappled (escape DC 15). Until this grapple ends, the target is restrained and takes 5 (1d10) bludgeoning damage at the start of each of its turns.
Grasping Surge (Recharge 5–6). The ground in a 20-foot radius centered on the Corrupted Soul Mangrove erupts with violent roots. Each creature in that area must make a DC 15 Dexterity saving throw. On a failed save, a creature takes 13 (3d8) bludgeoning damage and is restrained. On a successful save, the creature takes half as much damage and is not restrained. The area becomes difficult terrain until the end of the mangrove’s next turn.
Spore Burst (Recharge 6). The Corrupted Soul Mangrove exhales a dense wave of toxic spores in a 30-foot cone. Each creature in that area must make a DC 15 Constitution saving throw. On a failed save, a creature takes 18 (4d8) poison damage and is blinded until the end of its next turn. On a successful save, the creature takes half as much damage and is not blinded.
Reactive Roots. When a creature the Corrupted Soul Mangrove can sense leaves its reach, the mangrove makes one Root Slam attack against that creature.
Enter the description for how legendary actions work for your monster here.
Legendary Action Name (Costs # Actions). Enter the description for your legendary action.
Root Cataclysm (Costs 2 Actions). The Corrupted Soul Mangrove causes its roots to violently erupt outward. Each creature of its choice within 20 feet must make a DC 15 Strength saving throw or take 14 (4d6) bludgeoning damage and be knocked prone. On a successful save, the creature takes half as much damage and is not knocked prone.
Spore Pulse (Costs 2 Actions). The Corrupted Soul Mangrove releases a concentrated burst of toxic spores. Creatures of its choice within 30 feet must succeed on a DC 15 Constitution saving throw or take 10 (3d6) poison damage and be poisoned until the end of their next turn. On a successful save, they take half damage and are not poisoned.
Grasping Reclaim (Costs 3 Actions). The Corrupted Soul Mangrove targets up to two creatures it can sense within 30 feet. Each target must succeed on a DC 15 Dexterity saving throw or be pulled up to 20 feet toward the mangrove and be grappled (escape DC 15).
Description
The Corrupted Soul Mangrove is not a creature of thought, but of instinct and imbalance. It does not hunt out of hunger, nor does it act with malice in the traditional sense. Instead, it reacts violently to disturbances within its domain, lashing out at anything that moves through the water or disturbs the fragile ecosystem it has come to dominate. Its aggression is sudden and overwhelming, but limited in range—it does not pursue prey far beyond its territory.
It relies on its immense size and control over the surrounding swamp to overpower intruders, using grasping roots to restrain and crush while choking the air with toxic spores. It prioritizes creatures that struggle the most or deal the greatest harm, especially those wielding fire, which it instinctively recognizes as a threat. Despite its corrupted state, there are moments where its movements seem almost hesitant, as if something deeper within it resists the destruction it causes.
At its core, the mangrove is a manifestation of nature thrown out of balance—an ancient force twisted by outside influence. It does not communicate, cannot be reasoned with, and shows no signs of understanding language. However, its actions suggest a territorial awareness and a warped purpose, as though it is both guardian and victim of the corruption that gave it life.
Lair and Lair Actions
The lair of the Corrupted Soul Mangrove is a warped section of swamp where the natural order has begun to rot from within. The water is thick and sluggish, coated in a film of decaying organic matter, and the ground shifts unpredictably beneath each step. Massive mangrove roots dominate the area, forming natural walls, archways, and suffocating choke points.
A constant haze of spores hangs in the air, dimming light and muting sound. The swamp feels alive—but not in a natural way. Subtle movements ripple through the water even when nothing disturbs it, and distant creaking echoes as if the land itself is breathing. Creatures native to the swamp avoid this place entirely, leaving it unnaturally quiet aside from the low, groaning hum of the mangrove itself.
Lair Actions
On initiative count 20 (losing initiative ties), the Corrupted Soul Mangrove takes a lair action to cause one of the following effects.
Sinking Mire. A 20-foot-square area of ground the mangrove can see becomes thick, sucking mud. Each creature in that area must succeed on a DC 14 Strength saving throw or be restrained until the start of the next round.
Root Lash. A massive root lashes out at a creature within 60 feet. The target takes 9 (2d8) bludgeoning damage.
Whispering Rot. Illusory faces form in the surrounding bark and water. Creatures of the mangrove’s choice within 30 feet must succeed on a DC 14 Wisdom saving throw or have disadvantage on their next attack roll or ability check.
Regional Effects. The region containing the Corrupted Soul Mangrove is warped by its presence, creating the following effects:
Oppressive Spores. A faint spore haze lingers within 1 mile of the mangrove. Non-hostile creatures have disadvantage on Wisdom (Perception) checks that rely on smell, and open flames burn dimly, shedding half their normal light.
Unsettled Waters. Water within the region moves subtly against natural currents. Creatures traveling through swamp water treat it as difficult terrain, even if it normally would not be.
Withering Balance. Plant life in the area grows unevenly—some patches flourish unnaturally while others rot and decay rapidly. Magical effects that restore hit points within this region heal 1 fewer hit point per die rolled.
Silence of the Wild. Beasts instinctively avoid the area. Natural wildlife is scarce, and any beasts encountered are unusually skittish or aggressive.
Comments