Keen Smell. The troll has advantage on Wisdom (Perception) checks that rely on smell.
Swamp Camouflage. The marsh troll has advantage on Dexterity(Stealth) as long as it's in a swamp.
Regeneration. The marsh troll regains 10 hit points at the start of its turn. If the troll takes fire damage, this trait doesn't function at the start of the troll's next turn. The troll dies only if it starts its turn with 0 hit points and doesn't regenerate.
Stench. Any creature that starts its turn within 5 feet of the marsh troll must succeed on a DC 16 Constitution saving throw or be poisoned until the start of its next turn. On a successful saving throw, the creature is immune to the troll's Stench for 24 hours.
Surprise Attack. If the marsh troll surprises a creature and hits it with an attack during the first round of combat, the target takes an extra 7 (2d6) damage from the attack
Hold Breath. The marsh troll can hold its breath for 15 minutes.
Multiattack. The troll makes three attacks: one with its bite and two with its claws. If both of the claw attacks hit the target the target is grappled (escape DC 15).
Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) piercing damage plus 7 (2d6) acid damage
Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage plus and the target must make a DC 16 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one.
Description
Marsh trolls live in swamp taking form of brown-skinned giants covered in moss and decaying plant material. Since their strong natural acids can dissolve most kinds of matter they eat anything they can catch or find and devour in a swamp. The marshtrolls especially hate fire and always try to extinguish any source of it as only fire can arrest the regenerative properties of a troll’s flesh.
Lazy Hunters. As the marsh trolls are especially lazy they hunt by laying in shallow standing waters and waiting for the prey to approach them. Their moss covered skin allows them to melt with the surroundings making it easy to mistake them for a rotting log. When the prey is near to them they spring from the water snatching it and dragging it into water with their hooked claws.
Decay Devourers. The trolls do not favor fresh meat rather klling their preys and letting them rot first for few days before they devour them. As they feed on decaying corpses and plants the bodies of marsh trolls can release foul odor. Their claws being used to feed on the decaying corpses are covered in layers of poisonous miasma which causes the flesh to rot much faster.