WastrilithLarge fiend (demon)
Amphibious. The wastrilith can breathe air and water.
Corrupt Water. At the start of each of the wastrilith’s turns, exposed water within 5 meters of it is befouled. Underwater, this effect lightly obscures the area until a current clears it away. Water in containers remains corrupted until it evaporates.
A creature that consumes this foul water or swims in it must make a DC 18 Fortitude saving throw. On a successful save, the creature is immune to the foul water for 24 hours. On a failed save, the creature takes 14 (4d6) poison damage and is poisoned for 1 minute. At the end of this time, the poisoned creature must repeat the saving throw. On a failure, the creature takes 18 (4d8) poison damage and is poisoned until it finishes a long rest.
If another demon drinks the foul water as an action, it gains 11 (2d10) temporary health.
Magic Resistance. The wastrilith has advantage on saving throws against spells and other magical effects.
Undertow. Once on its turn when the wastrilith is underwater, it can cause all water within 10 meters of it to be difficult terrain for other creatures until the start of its next turn.
Bite (1/turn). Melee Weapon Attack: +9 to hit, reach 2 m. Hit: 30 (4d12 + 4) piercing damage.
Claws. Melee Weapon Attack: +9 to hit, reach 2 m. Hit: 18 (4d6 + 4) slashing damage.
Grasping Spout (1/turn). The wastrilith magically launches a spout of water at one creature it can see within 10 meters of it. The target must make a DC 17 Reflex saving throw, and it has disadvantage if it’s underwater. On a failed save, it takes 22 (4d8 + 4) acid damage and is pulled up to 10 meters toward the wastrilith. On a successful save, it takes half as much damage and isn’t pulled.
No concoctions, maneuvers, or spells
All monsters in this system should have maneuvers or spells. You should add some maneuvers or spells to this monster. If you do so, please make a suggestion on github so I can finish adding maneuvers and spells to all monsters via https://github.com/mlenser/kryx-rpg-issues/issues/9