So, a plague demon. Covered in boils that squirt insects and a foul gas that surrounds it. Its mere presence makes fluids unsafe to drink. It can direct its swarms of insects to spread its plague. The insects burrow into your flesh, grab chunks of your life force, then fly it back to the Hezrou demon to consume.
By an act of concentration, it holds its insects in check from attacking its own allies, but it really doesn't want to.
Body horror incarnate.
Sometimes Warlocks will summon a Hezrou demon to foul the water of it enemies. Sacrifice a few peasants and bury them next to a stream or well.
Hezrou
Large fiend (demon), Chaotic Evil
Armor Class 16 (Natural Armor)
- Hit Points 126 (12d10+60)
- Speed 30 ft.
STR 18 (+4)
DEX 16 (+3)
CON 20 (+5)
INT 8 (-1)
WIS 12 (+1)
CHA 14 (+2)
- Saving Throws Str +7, Con +8, Wis +4
- Damage Resistance Cold, Fire, Lightning; Bludgeoning and Slashing From Nonmagical Attacks; all Piercing
- Damage Immunities Poison
- Condition Immunities Poisoned
- Senses Darkvision 120 Ft., passive Perception 11
- Languages Abyssal, Telepathy 120 Ft.
- Challenge 8 (3,900 XP)
- Magic Resistance. The Hezrou has advantage on saving throws against spells and other magical effects.
- Burrowing Insects. When a Hezrou is hit with an attack, Burrowing Insects emerge from its boils and attack every creature within 5'. This does 1d6+2(6) poison damage and the target must make a DC 13 Constitution save or become poisoned for 1 minute. If the creature is already poisoned by the Hezrou, the save automatically fails, extending the poison for another minute. Effects that cure disease also cure the poison.
- Maisma. The Hezrou emites a maisma of stench and biting insects. It forms a cloud of 20' radius around the Hezrou. This cloud is lightly obscured, creatures other than the Hezrou treat it as difficult terrain, and ranged weapon attacks that cross it are at disadvantage. Creatures who start their turn in the Maisma are attacked by the Demon's Burrowing Insects.
- Plague Clouds. As a bonus action, the hezrou can send a 15' radius cloud of Maisma and insects up to 60' away, or move an existing cloud up to 60'. These clouds last until dispersed by damage over nearly its entire area, a strong wind, if the demon dismisses it as a free action, or if they their center is more than 100' away from the Hezrou demon. The Hezrou demon can maintain up to 5 of these regions at a time. If undirected, at the end of the demon's turn they will move up to 30' towards a creature. They otherwise act like the Maisma the Hezrou demon emits.
- Corruption. Fluid within 100' of the Hezrou demon is foul smelling and corrupted. Anyone drinking fluid that has been within 100' of the Hezrou demon must make a DC 16 constitution save or become poisoned for 1 hour. Purify food and drink will remove this effect, even on magical potions. All creatures poisoned by this effect cannot regain HP. Effects that cure disease also cure this poison.
- Feast of Flesh. As a bonus action, the Hezrou demon may call its harvesters home. Boils form and insect burst filled with life energy from those the Hezrou demon has infected. The Hezrou demon regains 5 HP for every creature poisoned by it, or every creature who died since the end of its last turn while poisoned by it, within 100'. Every living creature the Hezrou draws energy from has its max and current HP reduced by 5. When they complete a long rest, they can consume a HD to recover 5 max HP. Creatures killed by this effect turn into festering corpses that emit the Demon's Corruption effect independently for 1d4 weeks on similar enough creatures (humanoid corpses will poison water for humanoids, etc).
- Demonic Sergeant. At the end of a short or long rest, the Hezrou demon can concentrate on not having its Maisma effect its allies. While it is concentrating on this, creatures it chooses are not poisoned by its Maisma aura. It really wants to feast on the flesh of its allies, so saves to maintain concentration on this are at disadvantage.
Multiattack: the Hezrou Demon makes a two Bite and one Claw attack.
- Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: (2d8 + 4) piercing damage
- Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: (2d6 + 4) slashing damage
Ok, damage budget.
11+11+13 attack routine=35*3+105
2,3 creatures poisoned, 1 harvest = 12, 18, 15 (and 15 healed)
Boils burst 2-3 times per round for ~24 damage
58 DPR. CR 9 offensive. ATK is 1 low, Save DC is 3 low, ATK is on par, so CR 8 offensive.
136 HP 1. +15 heal . Resists are worth at most +1/3 in my opinion (magical weapons are gonna be common), so 188, or CR 8.
Probably undervaluing those defensive features by RAW.
I made it resist all piercing. Piercing weapons simply fly through its festering flesh and out the other end.
Fighting this in a war would be terrifying. Its plague clouds would tear through the lines of your troops, and it would funnel the lives of your troops into its own life force.
Using reach weapons is recommended, as they aren't at disadvantage from the clouds, nor do you suffer from the exploding boils.
The poison now does 6 damage (without a save). And the save is repeated until failed. Because I like the idea of the poison relentlessly pounding on the PCs. The Plague Cloud lets it harass PCs who aren't in melee range, and is an amazing warfare ability.
The Corruption ability is a ribbon. It makes tracking them in the mortal planes much easier as well. Drinking potions to heal isn't going to be fun, as you first have to make a save against being poisoned, and if you are the healing doesn't work.
Feast of Flesh is pure body horror. The HP swing isn't that huge, but the idea of insects bursting out of you and carrying your life essence to the demon is just so squicky. It is also a top-notch warfare ability; with Plague Clouds deployed on enemy troop lines, you can easily have a dozen+ sick enemy troops, and each Feast of Flesh heals 60 HP on the demon. This demon when near civilians or low-level troops will punch way above its weight.